While Shift+1 prints the exclamation mark, the key "1" does not work!

When I press the key 1 on my laptop keyboard, it does not print anything on the screen, but Shift+1 prints !. I have this problem only with just with 1!

1. It doesn't matter which layout is in use, I tried different layouts and still 1 prints nothing.

2. I test the issue on a USB keyabord plugged to my laptop and still can't print it.

• My laptop: Dell Inspiron 5458
• OS Edition: 18.10, Kubuntu

xev output when I press 1:

FocusOut event, serial 40, synthetic NO, window 0x3a00001,
    mode NotifyGrab, detail NotifyAncestor

FocusIn event, serial 40, synthetic NO, window 0x3a00001,
    mode NotifyUngrab, detail NotifyAncestor

KeymapNotify event, serial 40, synthetic NO, window 0x0,
    keys:  2   4   0   0   0   0   0   0   0   0   0   0   0   0   0   0   
           0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   

KeyRelease event, serial 40, synthetic NO, window 0x3a00001,
    root 0x17b, subw 0x0, time 696147, (891,524), root:(891,528),
    state 0x0, keycode 10 (keysym 0x31, 1), same_screen YES,
    XLookupString gives 1 bytes: (31) "1"
    XFilterEvent returns: False

xev output when I press Shift+1:

KeyPress event, serial 40, synthetic NO, window 0x3a00001,
    root 0x17b, subw 0x0, time 697230, (891,524), root:(891,528),
    state 0x0, keycode 50 (keysym 0xffe1, Shift_L), same_screen YES,
    XLookupString gives 0 bytes: 
    XmbLookupString gives 0 bytes: 
    XFilterEvent returns: False

KeyPress event, serial 40, synthetic NO, window 0x3a00001,
    root 0x17b, subw 0x0, time 698223, (891,524), root:(891,528),
    state 0x1, keycode 10 (keysym 0x21, exclam), same_screen YES,
    XLookupString gives 1 bytes: (21) "!"
    XmbLookupString gives 1 bytes: (21) "!"
    XFilterEvent returns: False

xev output when I press 2:

KeyRelease event, serial 40, synthetic NO, window 0x3a00001,
    root 0x17b, subw 0x0, time 694954, (891,524), root:(891,528),
    state 0x0, keycode 11 (keysym 0x32, 2), same_screen YES,
    XLookupString gives 1 bytes: (32) "2"
    XFilterEvent returns: False

xmodmap -pm

xmodmap:  up to 4 keys per modifier, (keycodes in parentheses):

shift       Shift_L (0x32),  Shift_R (0x3e)
lock      
control     Control_L (0x25),  Control_R (0x69)
mod1        Alt_L (0x40),  Alt_R (0x6c),  Meta_L (0xcd)
mod2        Num_Lock (0x4d)
mod3      
mod4        Super_L (0x85),  Super_R (0x86),  Super_L (0xce),  Hyper_L (0xcf)
mod5        ISO_Level3_Shift (0x5c),  Mode_switch (0xcb)

Narrow it down to hardware or software

First check to see if it is OS software, Application Tools or Laptop BIOS which is causing interference:

1. Boot with Live USB and select "Try Ubuntu without Installing". Does the 1 key work properly? If not try step 2. If yes reinstall Ubuntu 18.10.
2. Boot your laptop but interrupt Grub by pressing c key for command. Does the 1 key work properly? If Yes it is a problem with Ubuntu 18.10. If not go to step 3.
3. Get a USB keyboard (they start at $10 if you can't borrow one) and plug it in. Boot your laptop normally. Does the 1 key work properly? If not try step 4. If yes check Dell Update website and install this:
4. Try using Windows 7/8/10. Does problem still exist?

By removing ~/.config/kglobalshortcutsrc file, now that it's reset, I can type 1 by 1. My OS is Kubuntu and maybe there's kinda conflict by assigning new shortcut for Yakuake drop-down terminal or other software. But I don't know the exact reason for the issue.