This has occurred numerous times over years now. I tend to doubt it's particular to this installation, because it's appeared on every installation I've had for a long time. More of a straight report than a request for help tbh.
When there is a switch in the matrix by KS and a KS to a cell in the dimensions at the same time, the cell switch variously fails (not 100%, somewhat consistently but it could get it right some of the time), either to switch at all, or last night switching to the wrong key. Not always the same wrong key, more often than not has been consistent, but close the VI channel and come back it may be a different mistake. EDIT: it is not 'in every case', but it happens frequently enough to be maddening.
Happens on render as well. Placing the switch earlier is not a solution as far as I can determine, and not always viable anyway.
Latency settings do not appear to be particulary meaningful here either. Right now I do 192 samples which my audio interface assesses as round-trip 8.5ms. But same thing on a much less robust machine with 512 or more, and/or with no audio interface, etc.
This is in VE Pro 7, VI Pro both most recent version. It may be more prevalent in larger projects but I wouldn't be confident to assert that as a fact. Chances seem higher that if there is double switching _and_ a vertical dimension switch by CC that it will fail, but I cant show that statistically without being very methodical, and it doesn't seem it would be too fruitful to embark on that mission either. I was looking at a pretty involved preset it would be a problem to reconstruct say inside a single matrix to work around it, but I isolated it to a specific change I could and did effect.