*guy stabs you through the spaces in your ribs and penetrates your heart with his blade*
STEEL PLATED HEART
The real asspull there was him not seeing Uryuu's silver arrow coming. There's only so much a paralyzed Yhwach could do against Ichigo's ridiculous powerlevel without overwriting the future.
>Bombs falling everywhere, Genki clearly outside the shelter and gets blown away
>Two episodes later take female character from completely different generation of Getter and just have her suddenly become Genki whow was a girl all along
>This also means she was magically both outside the shelter and on Musashi's back at the same time
>The real asspull there was him not seeing Uryuu's silver arrow coming
Even if he did there's nothing he could do about it once it made contact; you have to remember Yhwach's real power isn't future sight but "changing the future", therefore if the arrow has already prevented Yhwach from changing his future then predicting the outcome is also impossible.
So yes it's still an asspull but no less than any other power that also affects causality.