Does your admin or whomever sets up machines have a list or template for what is added to each workstation on a fresh install?
As it isn’t related to environment variables, it must be elsewhere and I’m thinking it might be a Windows update of sorts.
If you could get a list of things added to your system, or screenshot your “Add and Remove Programs” dialog, we might get a clue as to which one is causing the issue.
One last thing, when you launch Nuke etc. from this clean environment, you were running
nuke.exe directly, and not one of your wrappers? It’s important nothing else is added so we know where to look.