In the current state of the game, the flashlight can function either when held in hand or if it's in the inventory on the chest rig slot. In this case, it attaches to the chest and can operate from there.
However, for Soviet soldiers, dy default the flashlight appears in the jacket slot, and for some reason it works as long as it's not moved out of this slot and back. Once moved, it works as intended, operates from the chest only if placed into the chest rig.

Solution: The flashlight should default to appearing in the chest rig slot, rather than the jacket, to ensure consistent functionality.