HVAC automatic damper in zoned system
1 It sounds like it was installed according to standard engineering practices.
2 This type of installation is usual and customary practice by today's standards.
3 Sounds like the home inspector is out of his depth.
4 Have the original installed write a letter to the above effect.  That should do it.
1 These type of dampers are fairly tight.  They are gasketed.  You should see very little air movement in the area not calling.