Was it a glitch or something like that?

Question

I was playing Pokemon White. I talked to that old lady in the Icirrus city Pokemon center and she gave me Brick Break (TM 31) and I taught it to my seismitoad ( I made him forget Rain Dance). I went to the gym right after that.
When I battled in the gym, Brick Break, that have a 15 PP, had only 5 PP left. So, was it a glitch or it happens when you replace a move with a TM with more PP?

Comments

Yeah, that's right. Just go to a Pokémon Centre to fix it.

Answer 1

It happens when you replace a move with a TM with more PP. I had a Reshiram, I was noobish back in the time, and made it forget Fusion Flare in Pokémon Black for Fire Blast in the league where Fusion Flare had no PP. I saw that Fire Blast too had no PP. I replaced it with Flamethrower, nothing. 0 PP. It happens when you replace a move with low PP by a move with Higher PP, like in your case.

Source: Experience.

Comments

Yeah, otherwise it would be restoring your PP.

Answer 2

Rain Dance has 5 PP.Brick Break has 5 PP because you replaced Rain dance with it.