The wait blocks are just a left over from trying to troubleshoot. I had any potential error appear after 2 seconds so I knew when the file would have finished playing.
Seems like a pretty clear bug to me. Your blocks are really simply and there’s nothing else I can see that might contribute to an issue such as a special character in the filenames.
It’s highjacking the sound file after the second click:
If I click ‘rim’ > ‘kick’ then every click of either button after that will be ‘kick’
If I click ‘kick’ > ‘rim’ then every click of either button after that will be ‘rim’