RSSI sensor lost in the multiprotocol module

[fdapport]

Hardware: Tandem X20s
Version Ethos: 1.5.19 FLEX
Multiprotocol Module Firmware V. 1.3.4.0
Receiver: RadioMaster R86 6chs, Frsky R8 protocol

All works ok, the only an unusual behavior is the RSSI sensor. If I search sensors I found the RSSI sensor but it is NOT showed in the top/right of the screen of the radio, see first picture.
If I delete the RSSI sensor from telemetry screen the RSSI indicator comes back in the top/right screen and also comes back the functionally of the lost sensors if I switch OFF the receiver. See second picture.
How it is possible this behavior? It is some thinks wrong in Ethos or in the Multiprotocol firmware?
It is some thinks that I need to configure in the telemetry sensors configuration?