Edit:
I’ve managed to fix it. The root problem of this error is the bone compression settings are not being loaded properly. From my understanding, they are loaded when this function is called.
UAnimBoneCompressionSettings::GetPreloadDependencies()
And that event is only called when EDL is enabled, so if you have it disabled, you must enable it and fix any errors EDL may give you. For me, EDL caused issues if I called
ConstructorHelpers::FObjectFinder<>
in the constructor of a class. So my solution was to either remove all
ConstructorHelpers::FObjectFinder<>
calls or move them from the Constructor to BeginPlay or Init functions.