Hey Asblom, thanks for replying here... If no one's keeping the thread alive or reporting the same issue, then it kinda loses priority (speaking from experience with support in general, not just Waldorf)...
I just received a reply from Waldorf support, and have been told they are indeed aware of this issue and are working on a fix.
I also received (a yet unpublished) FW v1.28, and successfully flashed my STVC with it, but this one still did not fix the vocoder volume issue.
However, something interesting happened after flashing - vocoder volume misbehaviour got temporarily reversed - Right channel was louder than Left - but only until I turned the STVC off and back on again. Then it returned to its previous misbehaviour, Left louder than Right.
After this happened, I'm pretty sure it's a FW bug and not a HW fault, and as such should hopefully be fixed sooner than later, especially if this issue is present on many (or even all) STVCs... I'm just sorry to see some poeple like you had been waiting for more than half a year to get this fixed, that's really not commendable, indeed...
I have to say that Vocoder output volume otherwise even at max is not that loud compared to string/synth section, so I find I actually have to have it at max all the time when connected to other equipment, so if anyone from Waldorf is reading this, I'd suggest while fixing this volume/panning issue maybe it would be a good idea to also make the vocoder section a bit louder, so it's comaprable to string/synth section...