[NinjaMunkeeNao]

Wiffle balls (or fuel) can take a lot of pushing around but once pressure is applied to them they tend to crack kinda easily. One thing is that the balls you purchased aren't (I'm assuming anyway) official FIRST game pieces, so there's a possibility the actual fuel pieces aren't as frail? There are a lot of knockoffs that break easily.

But don't feel bad about it! Like I said, Wiffle balls tend to crack if pressurized enough so I think everyone, even refs and rest crews are expecting to see a lot of cracked pieces throughout the day and probably won't point any fingers about it.