I have this same problem but with 2 screens, and I don't think it's a Windows scaling issue or at least it's not the main issue, if it was then it wouldn't be scaled wrong on both monitors as scaling would only be applied to the 4K screen would it not?
Also if it was a Windows scaling issue then the problem would be evident elsewhere not least of all in the previous version of Cue, but if it was a problem with the new version of Cue then you'd only see it with Cue, which is incidentally what we're seeing here.
