Windows build number: Microsoft Windows [Version 10.0.18362.418]
PowerToys version: 0.12.0
PowerToy module for which you are reporting the bug (if applicable): Shortcut Guide
This issue occurres since 0.12.0 before I couldn't observe this issue.
Long press the Windows key, the shortcut guide opens, release the windows key and the shortcut guide closes and the xbox gamebar opens
The shortcut guide opens and closes normally and does not launch xbox game bar
The shortcut guide opens and closes normally and after close lauches the xbox game bar

@StiviiK thanks for the report.
The issue is caused by Shortcut Guide sending fake keystrokes to prevent Start menu from appearing. Looks like the "undefined 0x07 key-code" is, in fact, the Xbox Guide button. As a workaround, you can disable this option in the game bar settings:

Most helpful comment
@StiviiK thanks for the report.
The issue is caused by Shortcut Guide sending fake keystrokes to prevent Start menu from appearing. Looks like the "undefined

0x07key-code" is, in fact, the Xbox Guide button. As a workaround, you can disable this option in the game bar settings: