The change to Trauma Patches feels like it breaks something fundamental on a couple different levels.
First, overflow as I understood the idea was literally parts being blown off you. You didn't just have a hole in you, you'd lost *chunks*. When you were down the Trauma Patch was only ever an auto stabilize. You still had penalties and problems arising from Overflow if you survived. Now, it's just "apply the miracle patch and it never mattered".
The idea that a Trauma Patch can heal damage boxes is pretty game changing in itself, but then again, "overflow" also been redefined as this nebulous "extra damage", which makes that concept nearly meaningless. You basically just have a vast extra reservoir of hit points that exist after you've been dropped. They really only serve to soak a bunch of extra damage and still let you survive, and which have different healing mechanics, since they can be healed with any number of Trauma Patches, which somehow stop helping you after they hit this arbitrary cap. It's like "damage but not damage" combined with "Healing potions that only work on the extra damage".
Like most of 6E, it's another spot in the rules where things make zero sense, and break something that wasn't broken before.
Here is a case where omission may as well be permission. Nothing says you can't, so you may as well. Overdamage works differently than regular damage, so there's nothing to stop you from putting on all the TPs you need to to heal it to 0, and then do the medkit and 1 action heal spells because I guess we're playing D&D now.