Aegislash stance change bug?

[Lorisaur 72]

Looks like I've found a small Aegislash bug:

 

I had a substitute and I was in shield form. After having attacked, the sub disappeared but it only was a graphic bug and that's ok. I received a hit afterwards and the sub took damage instead of aegis, altough the sub being unvisible. I had than king shielded but Aegis did not change form. I thought it was a graphic bug again, but it wasn't and Aegislash became unable to turn into shield form until I switched him out. This afternoon I'll try to do this again and post some screens if needed