I had strange results in this firmware.
Anything connected to my 2.4ghz band could not see other devices on the network.
5ghz had no problems seeing devices on the 5ghz or LAN.
I checked and isolation was off.
Reapplied firmware a couple of times and reset.
Downgraded and the problem went away.
I started having the same exact issues. I ended up reverting to 3341 and all is well again.