Power Up Glitch?

Have you used an IV calculator to verify that your Tyranitar is indeed 2.5 levels higher than your trainer level?

I've seen a similar thing happen, though not usually at trainer level cap. Sometimes when powering up it doesn't do the animation and none of the cost/cp numbers change. If you go to power it up a second time it will do the animation and account for two powerups at once instead of just one. Maybe that happened to you?

The game client for a long time was bugged to not allow powering above pokemon level 39, even though the game server would correctly accept powering up to 40. Players used a lot of tricks and work arounds to get their pokemon to max level 40 anyway. For players lower than level 38, these tricks also allowed getting pokemon higher than the (at that time) limit of 1.5 pokemon levels above their trainer level.

One way to accidentally power up higher was just innocently having poor reception. With bad reception sometimes inputs are read multiple times, so a single power up can be read as multiple power ups. It still costs the same amount of candy and stardust as though you actually told it to power up that many times.

This has also been complained as a single TM use using multiple TMs and ending with the same move. Niantic support denies that this is even possible and can't do anything to reverse it. From their side it looks like you used multiple TMs.