Fighting a team with That's All Folks! reduces your crit rate by 60%, just FYI, so that seems pretty normal actually. From personal experience, I can tell you it's annoying surprise though, and I still forget it sometimes!
Okay, to also include a fun story in this post. I was completely flubbing a fight, Firefly vs Harlequin, have only the tiniest scrap of life left and she goes into Diamonds are Forever, and I *don't* block.
It's a crit, I reflect the damage with Tainted Blood, and somehow win by losing, with Cerebella fainting to the floor while I'm still flying through the air like a bug on a string.
Also vs Cerebella, when I'm using Parasoul against her I seem to pretty regularly finish the fight with Parasoul's BB3. And *every* single time, I swear, Parasoul says "Your boss won't go so easy on you" and I'm like, "Jeeze, are you sure, Parasoul? You literally just shot her a million