Hello,
All in the title, here I'm trying to refill fireworks but as you can see it's briefly shown as 64 but then ends at a single one.

After trying a few other times it ended up working once. But I would say, 1/10 times it works.

Hello @Th3Dandy,

Are you playing on a server? Which mods do you have installed?

Hello,

Sorry for the late response. Yes, I play on a server, about the mods I tested on a clean instance with no mods and still nothing.
Can't upload videos for some reason, ask me for details.

After testing seems like it's because i'm playing on a server. I'll close this as unexpected, tho if you got an easy fix for it I would appreciate.