Hello!
I was jus in trying to do my second flight on the A350 when this happened. From previous posts, it seem to be related to WASM crashing.
I was trying to input a route to the alternate flight plan while enroute, but to my surprise this function in the FMS doesn't seem to behave correctly, since it does not allow for any entry on the ALTN route and any waypoint that I tried to insert got placed as next active waypoint. After a lot of trial and error, I somehow managed to get the whole active flight plan erased. I had a copy of it on SEC 1, but when I tried to swap it to active the whole cockpit froze. No systems or buttons worked, but the simulator kept running. Was flying on MSFS2024. I bought the product after the 1.0.4 update and did one flight successfully.