Transponder issue with the Mooney Ovation in FS2020

[Mehdi Goyat 0]

Hello, I tried to fly on Vatsim today on an EGPH-EDDC VFR trip.

I was able to tune into and communicate with Ground and obtained a clearance with a xpdr code. I input the code into the Mooney transponder panel, but ATC couldn't "see" the squawk change. I tried to shut the xpdr off, than back on, to reinput the code, connected/disconnect vPilot, nothing. Precision: it was originally set on 1200 when I switched avionics on (the defaut MSFS squawk), but I set it to 7000 initially before getting the clearance. The last code ATC could see was 7000.

I wonder if there's something at play in MSFS where only 1 squawk change could be "recognized" ?