So crazy that in my 10 years of using WaveLab, this only happened once and it was not long after the original post. Either it’s a new bug, or necromorbus found a needle in a haystack.
My takeaway here is that if it ever happens again, play with the file naming, or deal with reorganizing the files on two tracks as intended.
Hopefully when PG has time he can look into the true cause of it.