No, I do not have automatic saving enabled. The next day I tried to do a flight between VTBS and LFPG, and a second bug appeared after about 10 hours of flight: everything froze, it was impossible to disconnect the autopilot, etc. I only had engine sound and ATC still working. The aircraft was no longer following the flight plan. For your information, I had not activated FSLTL. I was forced to use (Alt + Del) to quit the game.
The following day I repeated the same flight and this time it worked. I was wondering whether the problem really came from the A350 or from MSFS 2024.