In my opinion this is a side effect of the obvious tweaking of AI behaviour/abilities since 13.1.
AI still blocks a lot of specials, even right after "save" combos. AI also uses dexterity in an almost Spidey-like manner, and if you get a combo in your block YOU SHALL NEVER EVER try a counter attack: In arena/AQ/AQ you'll definitely get parried (and combo'ed into oblivion).
The Game Team has tried to remedy the blocking issues with faster special attack animations (e.g. Scarlet Witch SP1), but this is just treating symptoms instead of curing the underlying condition: AI recovery thresholds have to be
carefully re-adjusted!
The parry issues seem to be result of either parry now having some sort of cooldown after an MLLLM combo (thus either resulting in a block or just eating a full combo (since your champion didn't even raise his guard in time despite perfect parry timing) OR AI tweaking.
Nevertheless, this NEW problem has (for me) begun to occur in v15.0: AI gets struck by a multi-hit special and interrupts the special attack animation by recovering and blocking mid animation! Evidence of this can be found
here.
Hopefully this gets fixed ASAP (along with the other issues which definitely seem to have a common origin in altered AI behaviour/abilities)!