Having the option to use Vigor in some spells

Okay, on closer evaluation, I noticed that these faux crits do happen even with regular attacks. I took an enemy with 65535 hp and bashed away. Headdy's usual 90 dmg attacks get turned into 123 very occasionally. They aren't crits because they don't make the screen flash, and Twila's actual crits deal twice her normal damage (82-164). This...is quite strange.

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...Okay, so I figured out what happened.
Battle starts at normal, numbers dealing base damage.

Character does a random crit, does x2 damage.
Character keeps doing faux crits of around +25% damage.
Character crits again, dealing x2 damage
Character now does base damage.
Character does another random crit, does x2 damage.
Character keeps doing faux crits of around +25% damage.
Character crits again, dealing x2 damage
Character now does base damage.

It loops.
When this happened I was like "Whaaaaaa!?"
So now we know what happens. Now how could we fix this?

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And upon even FURTHER investigation, I've come to another conclusion: each character reacts differently
Edgar descibes the scenario I pictured above.
Locke, after a crit, first deals one regular damage attack, then starts dealing faux crits until another crit, the next turn dealing normal damage, then faux crits until real crit. Pattern repeats.
With Terra the contrary happens: after a crit, it deals a faux crit, then starts dealing regular damage until a crit. The next turn is a faux crit and then normal again until another real crit.

What is this sorcery