I had this same problem. Updating from 5.5.0 to 5.5.4 seems to have fixed it. Though clicking “promote to parameter” still caused a crash (albeit a different one: Assertion failed: Count>=0 [File:D:\build++UE5\Sync\Engine\Source\Runtime\CoreUObject\Public\UObject\UnrealType.h] [Line: 3984]), but creating a parameter manually worked and I was finally able to bind it without the engine crashing.