BTT doesn't activate shortcuts

I have a shortcut in Apple Shortcuts which activates a shell script. It works when I trigger it in the Shortcuts app directly. It triggers with the quick action shortcut assigned to it in the shortcuts app. But it doesn't work when triggered in BTT. Not when it is assigned to a StreamDeck button and not when it is assigned to a Keyboard Shortcut in BTT.

I have no idea where I should even start looking for what causes this. Any suggestions?

I have had the same script as a script action in BTT but it stopped working, so I moved it into a shortcut. So the same script has previously worked inside BTT but now doesn't work anymore. I suspect it will start working again once I restart the computer, but that doesn't solve the root problem.

Quick update: when I restarted BTT, it closed the BTT window, gave me the beach ball for 30 secs or so, and then it pretty much crashed/froze. It wouldn't start any more, nothing. So I checked activity monitor and saw this:

So I suppose that Shell Script runner crashed and is blocking everything else. I force quit it.

Then I saw other BTT related processes:

I force quit these too, but BTT StreamDeck keeps coming back.

Starting BTT is still not possible. Will have to restart the whole machine.