Hi again,
I post here even if it's not about Jup-4 but about the same.
Something similar is happening in the OP-XA V and the Prophet 5 V.
Turn of Keytracking in both. When Cutoff is at max, then Env mod add to the cutoff. So does the Keytracking. The strange thing is, that if you add full Env modulation to the Cutoff, then the filter is opened so the cutoff does'nt add more filter. Perhaps only the cutoff is wrong or perhaps the cutoff and the Filter mod amount has been switched.
I'm not sure if the current behavior is correct behavior, but it seems odd to me and look like bugs. It at least is very strange that the Env mod amount by it self open the Cutoff more than the Cutoff can do by it self.
Will Arturia please have a look at this too?