This is not a bug at all, but rather a function of how Model Leader's stats from equipped moves, Signature Ability, and Marquee Ability interact -- in short, the perfect storm of reasons why she is one of the best defensive variants in the whole game.
- As a defensive variant, late-game players will often pack 40-50% Defense into Model Leader's moves.
- Model Leader's first Signature Ability gives her Armor with very high uptime, providing another 20% Defense.
- As a defensive variant, late-game players will often opt for the Blueshift Marquee Ability, providing up to another 40% Defense as long as the current combo count is 5 or less.
- With 5 stacks of Auto-Block, depending on your fighter and moves it can be very hard to get a 5-hit combo to shut off Blueshift. Getting Model airborne ASAP is a priority -- she can't Auto-Block you unless she's standing!
With all these factors in play, Model Leader with Blueshift active and a single stack of Armor can have up to 110% Defense, making her outright immune to damage from low-hit-count combos ... unless you have enough Piercing on your moves to get her back down below 100%. Strong offense-oriented Black Dahlias are your friend here -- her trademark Deadeye buff lets her breeze through all of Model's defensive perks, ignoring both Defense and Auto-Block.