v27 MAC 10.15.7 - When extracting parts some (not all!) of the string parts are simply missing some measures. These are not measures with rests (I don't think this is about multi-measure rests). If I copy that line (say the viola part) into a new document the measures are there; but when I extract the part they're gone. There are no staff styles in use that should be affecting those parts, and it doesn't do it with all the string parts, just a few. I can insert the missing bars, but hate to think that now I have to go through each part to ensure that all the measures are there. Any thoughts would be appreciated, thanks!