I am running CamDuct 2021, and still having this issue.  The only way to get the liner to flip is to check or uncheck the labels on underside box in the fittings database -> Pattern Switches -> Developments tab.  That is a global setting for all insulation, but the individual setting in the specific Insulation properties still does not flip the liner.  We also have certain liner types that either need to be label on underside or label on topside.  It is a drag to keep having to go into database every time we need to switch the global setting.  It leaves a large opportunity for cutting out the liner upside down if someone forgets to reset it every time the liner type changes.  Sometimes we even have multiple liner types in a single job so we have to get creative to make it cut out the correct way.