BTT overrides CMD-Tab even without a keyboard shortcut

The default behavior of CMD-Tab is being overwritten by BetterTouchTool so that it switches immediately to the next application instead of showing the switcher. This is deeply confusing. I don't have any shortcuts for "Application Switcher" and adding one manually didn't fix it. For now I'll have to stick with BetterSnapTool until this is fixed.

I have not seen such an issue before (and it works fine here).
Are you sure you haven't accidentally added a cmd+tab shortcut in the keyboard section in BTT?

It was a mistake I had in a key sequence! I'm trying to remap caps-lock to fn but it doesn't seem to be working. Is that possible or should I use Karabiner Elements?