HT Games
This behavior stems from the auto-save system combined with mission checkpoints. Auto-saves trigger at checkpoints during missions; if you quit mid-mission, the game saves that exact point. Restarting the mission from the pause menu ("Retry Mission") resets it to the start, while "Quit to Story Mode" (if available) saves without advancing the mission. To avoid unwanted progress: finish the mission before quitting, use "Retry Mission" for a clean restart, or on PC, manually back up save files before risky missions. Free-roam activities rarely have strict checkpoints, so this mainly affects story missions.