I have seen that on occasions in the spectator first person perspective mode that infantry units have a zooming effect, see video.
The unusual thing about this bug is that it only seems to happen if the player is the pilot of a helicopter or the driver of a boat (discovered so far) and you switch to spectate some infantry unit and view its first person mode.
Place a helicopter and make the player the pilot and give it some waypoints, or place a boat and make the player the driver, then place some infantry units and give them waypoints.
Then run the scenario and turn on spectator mode, then switch to viewing some infantry in first person perspective mode and you will see the zooming effect.
Below is the link to the google drive video.
I have discovered that private browsing mode in browsers MUST be turned off to stream view the videos on google drive.
File size is just under 40MB.