"Send Keyboard Shortcut" action of "A" bug

Hello,

I am experiencing the following error as demonstrated in the video below:

I am unable to create a "Send Keyboard Shortcut" action of "A". I can create other actions which include other letters however "A" always disappears.

I am able to set other keys for example "D" instead of "A", only "A" causes the above.

BetterTouchTool Version: 3.510 (1648)
macOS Big Surr 11.1
ARM MacBook Air 2020

Thank you in advance.