Right now, if an attack has both a Physical tag (Melee/Physically Ranged) and a Magic tag, the higher Protection of the target is... targeted, as in, vs its Defense and Resistance, whichever is higher will count as the reduction for that attack.
This is currently, as far as I am aware, only a thing over on the Peacebringer on their Arrow of Harmony. This really makes this unit, which is already struggling, struggle yet even more.
In my opinion, the lower Protection should be targeted. This will help out the Peacebringer, but also allow to play with these tags to give certain units a unique application for their role in combat, making them far more flexible!
Prime targets are the Dragons. During the Beta, they temporarily had Magic Strikes, meaning they targeted Resistance (with damage being reduced to 28). That helped their issue of not really being able to deal much damage against other high Tier units, despite their fat stats. Well, this got reversed due to Dragon Lords not dealing Magic Strikes, and giving them that also just not working with their skills, etc., so that change was reversed.
So why not just make Dragon's (the units, not the Hero) main attack Melee/Magic? Would fit half towards the Dragon Lords attack type! If such tagging targets the lower Protection, this will make them at last truly good units amongst the T5 roster, and help them stand out more, too! Would need to adjust (lower) their damage a bit, of course. Could stay as a Physical/Elemental split, too!
Another prime target is the Transmuter. They are currently in a Tome that adds a lot of -Def, and they themselves apply -Def, but they cannot benefit from -Def anymore with the Scorpion Patch, which is really awkward. So Physically Ranged/Magic tag their main attack! Would not apply any unwanted enchantments, anyways, because they don't get those applied to their class in the first place, and it would make them stand out as a unique Battle Mage, at long last!
The same goes for Warlock's curse being single shot unlike, say, Evoker's lightning.