Hi,
i recently tried out your plugin and it works quite well on 1.15.1. Apparently i still get some annoying errors in the console. It doesn't affect the plugin behaviour since i didn't notice something but here is is one out of the errors:
PreprocessCmd_err.txt

I tried to recreate this on the latest version of Paper (paper-229) and had no errors. Your version of paper is quite outdated (paper-62). Can you upgrade to the latest release to see if that fixes the errors?

sorry for my late reply. I wasn't able to upgrade earlier.
So the error stayed the same like this image below.

I downloaded then Parkour 5.2 and everything worked fine. So maybe something changed there that wasnt quite benifiting.

Edit: issue still remains. it didn't make any chances but it occurs after some time.

Reviewing this ticket with 6.0 codebase it doesn't appear as if anything can throw a NPE.
@Sylensky Are you able to join the support server to see if this still occurs with 6.0?