Curious behavior of a retail cart pkm

[Breyyne]

My Noctowl has been behaving rather oddly as of late.

During battles, it's pokeball will shake on the bottom screen.

According to what research I can track, that would indicate that it doesn't have full HP and/or a status condition.

Neither of these should be the case as I have taken it to the pokecenter on a number of occasions with no message from Joy about Pokerus and still it will shake during the first battle, and all others, after being healed.

If anyone has any insight into this it would be appreciated. I will use the PKM file that I extracted used HyperGTS.

Breyyne_Noctowl.pkm

[Pichu]

A shaking Pokéball means it's close to levelling up.