The problem only occurs when starting a mission (after the video of my troops landing). It seems to be related to the Fog of War graphics option? I deliberately chose the low setting for the attachment. The effect is weakened in Medium and High. My system works fine in other games.

Despite the question mark in your statement I cannot determine what you are asking to clarify. Yes, there is restricted vision before and after a team member exposes an area by entering and exiting any spot on the map.