I have a MB Pro w/Cat 10.15.5-keeps shutting down. It says "loading photos", goes black & restarts back to my sign in

panic(cpu 6 caller 0xffffff7f879a1ad5): userspace watchdog timeout: no successful checkins from com.apple.WindowServer in 120 seconds
service: com.apple.logd, total successful checkins since wake (3210 seconds ago): 322, last successful checkin: 0 seconds ago
service: com.apple.WindowServer, total successful checkins since wake (3210 seconds ago): 310, last successful checkin: 120 seconds ago

Backtrace (CPU 6), Frame : Return Address
0xffffff8205143720 : 0xffffff8006f1f5cd 
0xffffff8205143770 : 0xffffff8007058b05 
0xffffff82051437b0 : 0xffffff800704a68e 
0xffffff8205143800 : 0xffffff8006ec5a40 
0xffffff8205143820 : 0xffffff8006f1ec97 
0xffffff8205143920 : 0xffffff8006f1f087 
0xffffff8205143970 : 0xffffff80076c2838 
0xffffff82051439e0 : 0xffffff7f879a1ad5 
0xffffff82051439f0 : 0xffffff7f879a17fa 
0xffffff8205143a10 : 0xffffff8007654a8e 
0xffffff8205143a60 : 0xffffff7f879a0cfe 
0xffffff8205143b60 : 0xffffff800765dcb3 
0xffffff8205143ca0 : 0xffffff80070082b2 
0xffffff8205143db0 : 0xffffff8006f25328 
0xffffff8205143e10 : 0xffffff8006efbcc5 
0xffffff8205143e70 : 0xffffff8006f12aa2 
0xffffff8205143f00 : 0xffffff8007030d05 
0xffffff8205143fa0 : 0xffffff8006ec6226 
      Kernel Extensions in backtrace:
         com.apple.driver.watchdog(1.0)[B435C72B-B311-3C67-8AA1-1D5CE0FAD429]@0xffffff7f879a0000->0xffffff7f879a8fff

BSD process name corresponding to current thread: watchdogd
Boot args: chunklist-security-epoch=0 -chunklist-no-rev2-dev

Mac OS version:
19F101

Kernel version:
Darwin Kernel Version 19.5.0: Tue May 26 20:41:44 PDT 2020; root:xnu-6153.121.2~2/RELEASE_X86_64
Kernel UUID: 54F1A78D-6F41-32BD-BFED-4381F9F6E2EF
Kernel slide:     0x0000000006c00000
Kernel text base: 0xffffff8006e00000
__HIB  text base: 0xffffff8006d00000
System model name: MacBookPro15,1 (Mac-937A206F2EE63C01)
System shutdown begun: NO

System uptime in nanoseconds: 8580969081105
last loaded kext at 8160909490405: >!UAudio 323.1 (addr 0xffffff7f8c5c6000, size 434176)
last unloaded kext at 5611413460247: >!UAudio   323.1 (addr 0xffffff7f8c5c6000, size 434176)
loaded kexts:
@kext.AMDFramebuffer    3.0.9
@kext.AMDRadeonX4000    3.0.9
@kext.AMDRadeonServiceManager   3.0.9
>!AGraphicsDevicePolicy 5.2.4
@fileutil   20.036.15
@AGDCPluginDisplayMetrics   5.2.4
>!AHV   1
|IOUserEthernet 1.0.1
|IO!BSerialManager  7.0.5f6
>AGPM   111.4.4
>!APlatformEnabler  2.7.0d0
>X86PlatformShim    1.0.0
>!AUpstreamUserClient   3.6.8
>pmtelemetry    1
>AGDCBacklightControl   5.2.4
>!A!IKBLGraphics    14.0.6
@Dont_Steal_Mac_OS_X    7.0.0
>BridgeAudioCommunication   6.70.7
@kext.AMD9500!C 3.0.9
>!AThunderboltIP    3.1.4
>!AAVEBridge    6.1
>!AMuxControl2  5.2.4
>!AMCCSControl  1.14
>!ATopCaseHIDEventDriver    3430.1
>!AHIDALSService    1
>!ABridgeAudio!C    6.70.7
>!AGFXHDA   100.1.428
>!A!ICFLGraphicsFramebuffer 14.0.6
>!A!ISlowAdaptiveClocking   4.0.0
>!A!IPCHPMC 2.0.1
@filesystems.autofs 3.0
>BCMWLANFirmware4355.Hashstore  1
>BCMWLANFirmware4364.Hashstore  1
>BCMWLANFirmware4377.Hashstore  1
@filesystems.hfs.kext   522.100.5
@BootCache  40
@!AFSCompression.!AFSCompressionTypeDataless    1.0.0d1
@!AFSCompression.!AFSCompressionTypeZlib    1.0.0
>!AVirtIO   1.0
>!ABCMWLANBusInterfacePCIe  1
@filesystems.apfs   1412.120.2
@private.KextAudit  1.0
>!ASmartBatteryManager  161.0.0
>!AACPIButtons  6.1
>!ASMBIOS   2.1
>!AACPIEC   6.1
>!AAPIC 1.7
$!AImage4   1
@nke.applicationfirewall    303
$TMSafetyNet    8
@!ASystemPolicy 2.0.0
|EndpointSecurity   1
>!UAudio    323.1
@kext.AMDRadeonX4100HWLibs  1.0
@kext.AMDRadeonX4000HWServices  3.0.9
|IOAVB!F    850.1
>!ASSE  1.0
>!ABacklightExpert  1.1.0
@!AGPUWrangler  5.2.4
>!AGraphicsControl  5.2.4
>X86PlatformPlugin  1.0.0
>!ASMBus!C  1.0.18d1
>!AHS!BDriver   3430.1
>IO!BHIDDriver  7.0.5f6
>!AHIDKeyboard  209
>!AActuatorDriver   3440.1
>!AMultitouchDriver 3440.1
>!AInputDeviceSupport   3440.8
|IONDRVSupport  576.1
|IO!BHost!CUARTTransport    7.0.5f6
|IO!BHost!CTransport    7.0.5f6
>!A!ILpssUARTv1 3.0.60
>!A!ILpssUARTCommon 3.0.60
>!AOnboardSerial    1.0
@kext.AMDSupport    3.0.9
@!AGraphicsDeviceControl    5.2.4
|IOAccelerator!F2   438.5.4
|IOGraphics!F   576.1
|IOSlowAdaptiveClocking!F   1.0.0
>IOPlatformPlugin!F 6.0.0d8
@plugin.IOgPTPPlugin    840.3
|IOEthernetAVB!C    1.1.0
@kext.triggers  1.0
>usb.cdc.ncm    5.0.0
>usb.cdc    5.0.0
>usb.networking 5.0.0
>usb.!UHostCompositeDevice  1.2
|IOSurface  269.11
@filesystems.hfs.encodings.kext 1
|IOAudio!F  300.2
@vecLib.kext    1.2.0
>!ABCMWLANCore  1.0.0
>mDNSOffloadUserClient  1.0.1b8
>IOImageLoader  1.0.0
|IOSerial!F 11
|IO80211!FV2    1200.12.2b1
>corecapture    1.0.4
|IOSkywalk!F    1
>!AThunderboltPCIDownAdapter    2.5.4
>!AThunderboltDPInAdapter   6.2.6
>!AThunderboltDPAdapter!F   6.2.6
>!AHPM  3.4.4
>!A!ILpssI2C!C  3.0.60
>!A!ILpssDmac   3.0.60
>!A!ILpssI2C    3.0.60
>!AThunderboltNHI   5.8.6
|IOThunderbolt!F    7.6.1
>usb.!UVHCIBCE  1.2
>usb.!UVHCI 1.2
>usb.!UVHCICommonBCE    1.0
>usb.!UVHCICommon   1.0
>!AEffaceableNOR    1.0
|IOBufferCopy!C 1.1.0
|IOBufferCopyEngine!F   1
|IONVMe!F   2.1.0
|IOUSB!F    900.4.2
>usb.!UXHCIPCI  1.2
>usb.!UXHCI 1.2
>!AEFINVRAM 2.1
>!AEFIRuntime   2.1
>!ASMCRTC   1.0
|IOSMBus!F  1.1
|IOHID!F    2.0.0
$quarantine 4
$sandbox    300.0
@kext.!AMatch   1.0.0d1
>!AKeyStore 2
>!UTDM  489.120.1
|IOSCSIBlockCommandsDevice  422.120.3
>!ACredentialManager    1.0
>KernelRelayHost    1
>!ASEPManager   1.0.1
>IOSlaveProcessor   1
>!AFDEKeyStore  28.30
>!AEffaceable!S 1.0
>!AMobileFileIntegrity  1.0.5
@kext.CoreTrust 1
|CoreAnalytics!F    1
|IOTimeSync!F   840.3
|IONetworking!F 3.4
>DiskImages 493.0.0
|IO!B!F 7.0.5f6
|IO!BPacketLogger   7.0.5f6
|IOUSBMass!SDriver  157.121.1
|IOSCSIArchitectureModel!F  422.120.3
|IO!S!F 2.1
|IOUSBHost!F    1.2
>usb.!UCommon   1.0
>!UHostMergeProperties  1.2
>!ABusPower!C   1.0
|IOReport!F 47
>!AACPIPlatform 6.1
>!ASMC  3.1.9
>watchdog   1
|IOPCI!F    2.9
|IOACPI!F   1.4
@kec.pthread    1
@kec.corecrypto 1.0
@kec.Libm   1

I’ve encountered the same issue repeatedly and found a long thread on MacRumors with users sharing similar errors for the past few months. The most recent comments yesterday on page 19 report that Apple has a “Potential fix identified - For a future OS update”.