No telemetry using mavlink2, but RC works

Hi!
IM doing some tests with an old pixhawk (2.4.8 clone) and matek f405se Wing ( discontinued).

In both, IM using the same receiver, radiomaster RP3 configured using mavlink. The RC part IS OK, i can see and use RC in mission planner.
The problem is with telemetry…i cant receive It using pixhawk. If i plug the same receiver on f405, i can read ALL telemetry in my rádio (TX16S)…If i plug into pixhawk, i can see only telemetry from receiver iteelf, not arduplane.

In both controlers i have setup serialX_type as 2 ( mavlink2).
What am i missing?
Both systems im using serial 1 which has DMA on both controlers…
But i dont think communication between receiver and FC IS the problem, otherwise RC controls would not work, right?
IM using 4.5.7 in both FCs and elrs 3.5.3