Any other PLDS noticing this?

So far my Shelltron would occasionally not pop on Twin Bolt from O1S or Earth Shaker from O4S. I can't tell if I'm doing it too soon or too late. I would watch the Shelltron buff icon activated throughout the cast, but it would not proc EVEN THOUGH it was still on me after the move went off, a good 3-5 seconds of duration would still be there.

Blocking didn't work when casting. Maybe you were in HS spam phase?

Ohhh I did not know that. Thanks.

Yup i have done the same but at aero 3, after you learn the timings of the fight and pop it even before he starts casting it then proceeds to cast holy spirit and aero 3 hits you in the face for 57k :)