MR60/MS60: cannot ping wired devices from wifi network

With the MR60 + 2*MS60 configured as a router, my wired devices (e.g. a Synology NAS) could not be seen from my wifi devices (e.g. a Macbook Air), and vice-versa, but wifi devices could see one another.

Solution/workaround: I put my old TP-Link router back in place as a router, with wifi disabled, and then configured my MR60 as an access point.  Now my wired and wifi devices can all see one another.  I am back in business accessing my NAS from my Mac notebooks.  Unfortunately my upload speed in the workaround state is slower than with the MR60 in router mode, but at least my home network is now in a working state.  My wired devices (NAS + printer + voip telephone box) are attached to the MR60 ethernet port via a Netgear switch.  My old TP-link router now has just one ethernet cable to FIOS internet and one ethernet cable to the MR60 WAN port.

I would love to have some sort of firmware update that would allow traffic to/from the wired ports on the MR60/MS60 to be bridged/switched onto the wifi network, so that my wifii devices could talk with my wired NAS when the MR60 is in router mode.  Then I could finally discard my old TP-link router, which is slowing down my uploads, and whose security is probably less up-to-date than the new MR60's security.

Many thanks to Louie from customer support ticket # 43957276 who spent a lot of time trying several possible ideas to help me out via chat yesterday.  While we were not able to resolve the issue with the MR60 in router mode, I do appreciate the support.  I hope we can find out from the firmware experts whether this is a feature or a bug.