Hi Karl,
I do not believe GS intended that any version be transparently converted back to an earlier version. Rather, I believe that the goal was to convert as much as was easily possible. Certainly, converting from 8.1 to 6.5 would involve a huge loss of information because of the change from QuickViews (6.5) to View Sets (8.1) and much more.
So, problems with moving backwards to older versions have always existed ... and not just with AC, but with all software.
I would not hold your breath for improvements in 'down-conversion' unless there is a serious loss of actual model elements (beyond library parts, which are not usually downward compatible). IMHO GS's resources are best spent debugging and smoothing current features.
Sorry to hear about your frustration, though.
😞
Cheers,
Karl
One of the forum moderators
AC 27 USA and earlier • macOS Ventura 13.6.9, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB