@necromorbus: I tried l and r at the end with and without space and it works absolutely normal. Only when using L and R or l and r with dash or underscore preceding it at the end of the filename does the staggering feature fail. And for C, S it fails only with a dash. And as JimP has remarked, this is most likely connected to some internal Wavelab filename flags for Left, Right, Center and Surround. I’m certain for the Wavelab Dev team it’s no issue to fix, now that we have narrowed it down. A moderator just needs to make a bug report or CAN entry…
If you want me to recreate your issue with l and r, please post a video in which I can see your filenames. My guess is, you have a dash or underscore somewhere preceding the letter r or l (or a dash before c or s). If you have a filename with dash-r and one r without, it will still fail. But it will fail because of the former not the latter. Wavelab will stagger correctly until the file name with above criteria comes up, then it fails and starts staggering on multiple tracks. So its pretty simple to narrow it down.