MS60 strange behaviour

I have configured an MR60 with two MS60 Sitellites.

after last update to firmware 1.0.6.110 I've start to notice that network map provided by the app is showing one of the satellite no longer connected (purple dot).

in reality, both satellites are connected and are reacheble with a proper assigned IP.

if I'm accessing MR60 router page via brouser, I can see both listed. 

but if I run through update session, just one of the two is listed and has checked for updates.

I've tried everything, reboot, factory reset, firmware rollback as well as to reinstall latest. 

the problem remain. 

any suggestion?

many thanks.

AF