I can reproduce the issue by migrating the problematic asset and all the related assets to a clean project.
It’s a subclass of Character. And it doesn’t work even if I connect Add Movement Input directly to Tick(). Everything worked fine in 4.11 and everything works fine in 4.12 editor. Only the packaged game (64-bit Windows) has this problem and it’s hard to debug.
As I said - I can share the project that contains the problematic asset.