Thanks @Fae This issue seems to have resolved itself without any action on my part - same same hardware, same networking software, same settings, but zero RXBadPkt on any of my three switches.

Similar experience here, involving two Asus routers and two TP-Link switches, but with a slight twist: Setup 1: No Aimesh (i.e. Router 1 set in wireless router mode, Router 2 in wired access point)...