No, I did have Montage focused at the time. Oddly it became un-greyed a few minutes later and not due to anything I did - at lest as far as I can tell. It was kind of like it took a long time before it was ready to use & then everything was fine.
I’ve noticed some odd things a few times that were resolved by closing & reopening Wavelab. Once the play button didn’t do anything. Another time WaveLab was playing, meters bopping around but none of it going to my audio device. Checked the settings and the routing is all correct, focus is on Wavelab, still no sound. Both resolved by restarting.