MacOS kernel panics when unmounting Time Machine disk images over SSHFS mount

I made a simple Bash script to back up my Mac through Time Machine over network. It mounts a server through SSHFS using MacFUSE, mounts a HFS+ sparsebundle disk image inside that mount, and tells Time Machine to back up to it, unmounting them when it's done. It usually works just fine, but a kernel panic happens about once in every 6 or so times when it tries to unmount the sparsebundle disk image. The kernel panics seemed to happen both in MacOS Catalina and Big Sur. The same problem never changed even when I changed from a Macbook Air late 2015 to a 2020 MacBook Pro, so I believe the Mac hardware might be irrelevant.

Is there a way to tell if this is a problem relating to the Apple DiskImages driver, the MacFUSE kernel extension, or something different? Should I consult Apple or the maker of MacFUSE if there is no other way to correct this?

Here is the Kernel Panic backtrace:

panic(cpu 3 caller 0xffffff801ad85bc4): "wire_count == 0, m = 0xffffff8032fd02b0, obj = 0xffffff803d9b9d00\n"@/AppleInternal/BuildRoot/Library/Caches/com.apple.xbs/Sources/xnu/xnu-7195.81.3/osfmk/vm/vm_pageout.c:7572
Backtrace (CPU 3), Frame : Return Address
0xffffffa090a739d0 : 0xffffff801acbab4d 
0xffffffa090a73a20 : 0xffffff801adfd7e3 
0xffffffa090a73a60 : 0xffffff801adede1a 
0xffffffa090a73ab0 : 0xffffff801ac5fa2f 
0xffffffa090a73ad0 : 0xffffff801acba3ed 
0xffffffa090a73bf0 : 0xffffff801acba6d8 
0xffffffa090a73c60 : 0xffffff801b4bef9a 
0xffffffa090a73cd0 : 0xffffff801ad85bc4 
0xffffffa090a73e20 : 0xffffff801b42ad4f 
0xffffffa090a73e70 : 0xffffff801d2969c1 
0xffffffa090a73e90 : 0xffffff801d2960aa 
0xffffffa090a73eb0 : 0xffffff801d296000 
0xffffffa090a73ed0 : 0xffffff801b3fc9f7 
0xffffffa090a73ef0 : 0xffffff801b3f9a7d 
0xffffffa090a73f30 : 0xffffff801b41691e 
0xffffffa090a73f70 : 0xffffff801b415f06 
0xffffffa090a73fa0 : 0xffffff801ac5f13e 
      Kernel Extensions in backtrace:
         com.apple.driver.DiskImages(493.0)[11E51AF9-6467-39AC-89A2-A62CE763F298]@0xffffff801d295000->0xffffff801d2a0fff
            dependency: com.apple.iokit.IOStorageFamily(2.1)[B5300908-BF34-3D47-8776-FB154A6DEE4C]@0xffffff801d73f000->0xffffff801d750fff

Process name corresponding to current thread: kernel_task
Boot args: -v chunklist-security-epoch=0 -chunklist-no-rev2-dev

Mac OS version:
20D74

Kernel version:
Darwin Kernel Version 20.3.0: Thu Jan 21 00:07:06 PST 2021; root:xnu-7195.81.3~1/RELEASE_X86_64
Kernel UUID: C86236B2-4976-3542-80CA-74A6B8B4BA03
KernelCache slide: 0x000000001aa00000
KernelCache base:  0xffffff801ac00000
Kernel slide:      0x000000001aa10000
Kernel text base:  0xffffff801ac10000
__HIB  text base: 0xffffff801ab00000
System model name: MacBookPro16,3 (Mac-E7203C0F68AA0004)
System shutdown begun: NO
Hibernation exit count: 0

System uptime in nanoseconds: 11092066957957
Last Sleep:           absolute           base_tsc          base_nano
  Uptime  : 0x00000a1692b5fd2e
  Sleep   : 0x00000877d70daad5 0x00000bfb283e2420 0x000008693a36c209
  Wake    : 0x00000877e168dd7b 0x00000c4e1fdaf8c6 0x00000877e012bf29
last started kext at 11091852477214: >!AXsanScheme  3 (addr 0xffffff801c467000, size 12288)
last stopped kext at 10623433685325: >!AXsanScheme  3 (addr 0xffffff801c467000, size 12288)
loaded kexts:
io.macfuse.filesystems.macfuse  2053.20
org.virtualbox.kext.VBoxNetAdp  6.1.18
org.virtualbox.kext.VBoxNetFlt  6.1.18
org.virtualbox.kext.VBoxUSB 6.1.18
org.virtualbox.kext.VBoxDrv 6.1.18
>AGPM   119
>!APlatformEnabler  2.7.0d0
>X86PlatformShim    1.0.0
@filesystems.autofs 3.0
@fileutil   20.036.15
>!ATopCaseHIDEventDriver    4030.5
>!AHIDALSService    1
>!AGraphicsDevicePolicy 6.2.2
>!AUpstreamUserClient   3.6.8
@AGDCPluginDisplayMetrics   6.2.2
>pmtelemetry    1
>!A!IKBLGraphics    16.0.1
>LuaHardwareAccess  1.0.16
|IOUserEthernet 1.0.1
|IO!BSerialManager  8.0.3d9
@Dont_Steal_Mac_OS_X    7.0.0
>!AHV   1
>!ADiskImages2  1
>!A!ISlowAdaptiveClocking   4.0.0
>!ABridgeAudio!C    100.2
>!A!ICFLGraphicsFramebuffer 16.0.1
>!A!IPCHPMC 2.0.1
>BridgeAudioCommunication   100.2
>!AAVEBridge    6.1
>!ABacklight    180.3
>!AThunderboltIP    4.0.3
>!AGFXHDA   100.1.431
>!AMCCSControl  1.14
@filesystems.apfs   1677.81.1
>BCMWLANFirmware4378.Hashstore  1
>BCMWLANFirmware4377.Hashstore  1
>BCMWLANFirmware4364.Hashstore  1
>BCMWLANFirmware4355.Hashstore  1
>!A!BModule 1
@filesystems.tmpfs  1
@filesystems.hfs.kext   556.60.1
@BootCache  40
@!AFSCompression.!AFSCompressionTypeZlib    1.0.0
@!AFSCompression.!AFSCompressionTypeDataless    1.0.0d1
@private.KextAudit  1.0
>!ASmartBatteryManager  161.0.0
>!ABCMWLANBusInterfacePCIeMac   1
>!AACPIButtons  6.1
>!ASMBIOS   2.1
>!AACPIEC   6.1
>!AAPIC 1.7
@!ASystemPolicy 2.0.0
@nke.applicationfirewall    310
|IOKitRegistryCompatibility 1
|EndpointSecurity   1
>!AXsanScheme   3
|IOUSBUserClient    900.4.2
@kext.triggers  1.0
>!AHIDKeyboard  223
>!AActuatorDriver   4400.28
>!AMultitouchDriver 4400.28
>!AInputDeviceSupport   4400.35
>!AHS!BDriver   4030.5
>IO!BHIDDriver  8.0.3d9
>!AGraphicsControl  6.2.2
|IOAVB!F    930.1
>X86PlatformPlugin  1.0.0
@!AGPUWrangler  6.2.2
|IOSlowAdaptiveClocking!F   1.0.0
|IOAccelerator!F2   439.52
>!A!ILpssUARTv1 3.0.60
>!A!ILpssUARTCommon 3.0.60
>!AOnboardSerial    1.0
>IOPlatformPlugin!F 6.0.0d8
@!AGraphicsDeviceControl    6.2.2
>!ABacklightExpert  1.1.0
|IONDRVSupport  585
|IOAudio!F  300.6.1
@vecLib.kext    1.2.0
|IOGraphics!F   585
>!ASMBus!C  1.0.18d1
@plugin.IOgPTPPlugin    900.11
|IOEthernetAVB!C    1.1.0
>usb.cdc.ncm    5.0.0
>usb.cdc    5.0.0
>usb.networking 5.0.0
>usb.!UHostCompositeDevice  1.2
>!AThunderboltPCIDownAdapter    4.1.1
>!AThunderboltDPInAdapter   8.1.4
>!AThunderboltDPAdapter!F   8.1.4
>!AHPM  3.4.4
>!A!ILpssI2C!C  3.0.60
>!A!ILpssDmac   3.0.60
>usb.!UVHCIBCE  1.2
>usb.!UVHCICommonBCE    1.0
>usb.!UVHCI 1.2
>usb.!UVHCICommon   1.0
>!AEffaceableNOR    1.0
|IOBufferCopy!C 1.1.0
|IOBufferCopyEngine!F   1
|IONVMe!F   2.1.0
>!AThunderboltNHI   7.2.8
|IOThunderbolt!F    9.3.2
>IO!BHost!CPCIeTransport    8.0.3d9
|IO!BHost!CTransport    8.0.3d9
>!AConvergedIPCOLYBTControl 1
>!A!BDebug  1
>!A!BDebugService   1
>!AConvergedPCI 1
>!A!ILpssI2C    3.0.60
>usb.!UXHCIPCI  1.2
>usb.!UXHCI 1.2
>!ABSDKextStarter   3
|IOSurface  289.3
@filesystems.hfs.encodings.kext 1
|IOUSB!F    900.4.2
>!AEFINVRAM 2.1
>!AMultiFunctionManagerMac  1
>!AEFIRuntime   2.1
>!ABCMWLANCoreMac   1.0.0
|IOSerial!F 11
|IO80211!FV2    1200.12.2b1
|IOSkywalk!F    1
>mDNSOffloadUserClient  1.0.1b8
>IOImageLoader  1.0.0
>corecapture    1.0.4
>!ASMCRTC   1.0
|IOSMBus!F  1.1
|IOHID!F    2.0.0
$!AImage4   3.0.0
|IOTimeSync!F   900.11
|IONetworking!F 3.4
>DiskImages 493.0.0
|IO!B!F 8.0.3d9
|IOReport!F 47
|IO!BPacketLogger   8.0.3d9
$quarantine 4
$sandbox    300.0
@kext.!AMatch   1.0.0d1
|CoreAnalytics!F    1
>!ASSE  1.0
>!AKeyStore 2
>!UTDM  511.60.2
|IOUSBMass!SDriver  184.40.6
|IOSCSIBlockCommandsDevice  436.40.6
|IO!S!F 2.1
|IOSCSIArchitectureModel!F  436.40.6
>!AMobileFileIntegrity  1.0.5
@kext.CoreTrust 1
>!AFDEKeyStore  28.30
>!AEffaceable!S 1.0
>!ACredentialManager    1.0
>KernelRelayHost    1
|IOUSBHost!F    1.2
>!UHostMergeProperties  1.2
>usb.!UCommon   1.0
>!ABusPower!C   1.0
>!ASEPManager   1.0.1
>IOSlaveProcessor   1
>!AACPIPlatform 6.1
>!ASMC  3.1.9
|IOPCI!F    2.9
|IOACPI!F   1.4
>watchdog   1
@kec.pthread    1
@kec.corecrypto 11.1
@kec.Libm   1

panic(cpu 3 caller 0xffffff801ad85bc4): "wire_count == 0, m = 0xffffff8032fd02b0, obj = 0xffffff803d9b9d00\n"@/AppleInternal/BuildRoot/Library/Caches/com.apple.xbs/Sources/xnu/xnu-7195.81.3/osfmk/vm/vm_pageout.c:7572

This panic signature is identical to one that I've encountered myself with sudden removal of a disk image backing store. It's a bug in the macOS disk image driver, not MacFUSE (MacFUSE wasn't installed on my machine). You should report the panic to Apple. Giving them readily reproducible steps will be key to fixing the issue.