Component reset, caused by a simple setup (Demo project included)

Ok so this is the setup:

THE HISTORY:
I am building on the GenericShooter template. Been doing it since 4.6/4.7
and upgrading every step of the way, everything worked without any problem until 4.13 which gave me a problem with spawns and I had to wait for 4.14, 4.14 came and I had yet another problem related to that, 4.15, preview 1, 2 and 3 gave me all errors regarding enums, Async loading, and other packaging errors, enums have been messed on preview 2 but I’ve redone it so it worked as intended, preview 4 came out, and I finally managed to package the game.

THE ERROR:
4.15 preview 4 came and I packaged the game, everything went smooth and when testing the game, my character has a T pose with a -90 rotation, standing in the air… (see attachments, one is in editor/standalone the other one is the game packed. same skeleton, same parameters, same map even)

Everything in the editor works perfectly, standalone works perfectly as well, and when packaging the game, the character just resets, puts itself in -90 rotation and T pose.

EDIT:
ALSO need to mention: I am using a BP_playerCharacter as a parent, and I am using several children BP as different character.Exactly like the original problem was on the thread