Possible Flask Bug

I say possible because maybe there is some kind of coding that gives certain classes more uses, or something?

I made a flask on my highest level character, came out with 10/94. I refilled it on that character, shows 9 uses available. I transferred that flask to my slightly lower level character. Refilled it, shows 6 uses available. I've noticed this before with other flasks I transferred, and even with ones I created/found and used on the same character.

Example: found an 8/75 that only have 5 uses.

Is there some kind of bug with flasks? Why would they be giving me the true use-count on one character, but not on others?