[Imp]

This issue has already been addressed to a degree, it’s linked to turning a unit for the same effect which now has the option to create reaction fire and would probably need a complete recode to improve it further.
Borderline visible units may turn up on occasion but it’s no big issue it’s a 3 minute turn.
I assume you had not used the procedure above and fired at the area near the unit causing the situation to change.
This I am guessing is what most of us do.
If not and it’s a game mechanic you wish to exploit feel free, I for one could not be bothered with it and will continue trying to make units visible using the above method.