Bit of a strange one, but I can reproduce this reliably with only NA and JEI installed.

NaturesAura-37.5

Basically goes like this:

1. Run /naaura add 10000
2. Run /reload
3. Run /naaura add 10000 again. It will fail as an unknown command

Video: https://streamable.com/wbw4dm

I know, /reload isn't something that most people are going to do, and certainly not frequently, but it's leading to a few knock on issues for me. Namely, while developing I have to run /reload countless times to refresh recipes. This locks me out of running these commands if necessary.

It's also limiting my ability to use the commands for other more creative ventures, like running the commands as part of recipes to either add or remove some amount of aura as they occur.