[Floating HTML window] Keyboard shortcuts do not work randomly (CMD-A, CMD-V, ...)

Note: Before bug reporting, please make sure you have tried the latest (alpha) version of BetterTouchTool and that you have already tried to restart your system :-). If you encounter a crash, please attach a crash log from the macOS Console.app from the "User Diagnostic Reports" section.

Describe the bug
I use a floating HTML window to perform fast translation with Google Translate.
I open this window with a Keyboard keys combinaison trigger.
Inside the field to enter the text to translate, all the usual keyboard shorcutcs randomly do not work (CMD-A, CMD-C, CMD-V).
For example if you want to paste a text from your clipboard, when you press CMB-V you will have a "bang" sound from macOS, exactly when you try to paste a text on your desktop.
I am pretty sure that those shortcuts worked in the past.

Affected input device (e.g. MacBook Trackpad, Magic Mouse/Trackpad, Touch Bar, etc.):

If applicable, add screenshots to help explain your problem. (You can just paste or drag them here)

Device information:

  • Type of Mac: MacBook Pro 2015
  • macOS version: 10.15.4
  • BetterTouchTool version: 3.373

Additional information (e.g. StackTraces, related issues, screenshots, workarounds, etc.):