1. Join an official Bohemia game server.

2. Play for 15-30 minutes, or more, usually occurs when heavily populated, or maximum users.

3. Performing the 'F' key dig/build routine, routinely ceases caused by spurious other input, likely the scroll mouse wheel downward action. Although no known other keyboard (or other) input is occurring aside from using the 'F' keyboard key.

I also use TrackIR, head movement input, however nothing within TrackIR seems to be creating any spurious input.

This bug seemingly occurs after more than 15-30 minutes of game play, likely indicating other users are joining with modifications, causing server anomalies. This is very typically/commonly known bug with ARMA 3.

If I were paranoid, I'd almost say somebody is watching through my player's eyes (another common/old/fixed ARMA 3 bug), and possibly inadvertently activating their scroll wheel mouse down input action. Usually though, if this were the case, other keyboard input would also be occurring.