I'm also having this issue. I've had the addon for a while but just got back to pet collecting. Specifically right now this is when in the battle screen, it will just have a number instead of the pet breed. This is on the latest version (1.35.6), and to make sure there was no interference from other mods, I disabled PetTracker and Rematch.

Can you provide more information? It works fine for me right now.