It is known. I noted it when it was reported back in May and found the offending regression, but nothing has been fixed yet.
https://github.com/mamedev/mame/com...0f8b40eecd4a7db26#commitcomment-50585299

It was my bad for not following up and getting a MAMETESTERS bug report started on it.
I'll likely post it soon if no one else beats me to it.