I’ve noticed this for a while that some bosses have less charge than they’re supposed to at certain points but this morning I took Ozymandias for the green oni and each turn I NP’ed and sealed him, his charge bar would stagnate for that turn.
I think you just answered your own question
Just as you said it by yourself, NP seal will both prevent enemy from firing their NP AND will prevent their natural NP charge (except they use NP charge skills or of course, debuff removal)
I see, so charging skills will still work. It’s just that I had a wow moment when I realised what was happening since I didn’t think the np seal mechanic would work like that as well. I’ll start factoring that as well in the future when I prepare for enemy np’s.