When using the distance to the hitbox as the link condition,
the reaction stops working if an object group is specified.
(The target attack is placed in the corresponding group.)
It works when all groups are selected.
In the sample game’s PerfectDodge, even if you set up a link like the above from the player character’s state,
it can be confirmed that the dragon’s arm attack does not trigger a reaction.
(This occurs when the Enemy group is set as the condition; selecting all groups still works as expected.)
I believe this used to work in a previous version (though I can’t recall exactly when). Could you look into this?