OSD freezes when FrSky transmitter is switched on.

[SjDost]

I am using INAV8.0.1 on SpeedyBee wing F405 with a FrSky receiver (Sbus and Smartbus), For VTX I use the new Eachine Sphere unit.
INAV port config tab is;
UART2 : in RX column Serial RX is on
UART3 : in Sensor column GPS
UART5 : in Perepherals column "MSP Display port" (Data column: MSP is NOT toggled)
UART6 : in Data column MSP on
Softserial1 : Telemetry is SmartPort

In configuration tab OSD slider is on.
In OSD tab AVATAR is chosen.

The issue I now have is that as long as my transmitter is switched OFF the OSD info in correctly displayed on the separate OSD screen. But as soon as the transmitter is switched on the OSD display freezes. If the transmitter is switched OFF again the OSD also becomes life again. It looks to me as a protocol conflict.

The transmitter display itself shows telemetry info correctly (via the FrSky SmartPort and Port T4 on the SpeedyBee).

I am puzzled and out of options so any suggestion is very welcome.

[sensei-hacker]

I would use a meter to check for a short between either UART2 pad and either UART6 pad.

[SjDost]

Hi Sensei,
I have not been able to find any short so something else is going on.