> My main recollection of it is getting Java compiler errors because Scala constructs were being implemented with deeply nested inner classes and the generated symbol names were too long.

Sounds like you've used some beta version over 15 years ago.

Nothing like described happens in current Scala and it's like that as long as I can think back. Never even heard of such bugs like stated.

Coming up with such possibly made up stuff over 15 years later sounds like typical FUD, to be honest.