Sorry this is just now being addressed.
Looks like this issue is coming from the engine itself. The files can be imported/migrated with no issues into any 4.17 and 4.19 project no problem, but as soon as I try in 4.18 the issue becomes apparent. I’m not sure if this can be fixed until I hear back from Epic. If possible I’d upgrade to 4.19 as a quick fix.
EDIT: I might just rebuild the whole project in 4.18 from scratch so that way there is a working version without having to worry about if Epic knows what’s going on. No ETA on this rebuild for 4.18 though.