1. Join a multiplayer Official Bohemia server

2. Likely will require significant number of game play hours before witnessing this anomaly.

What should occur, the AI troops should spawn while the players are significantly much further away from the base, that the player intends to capture. However, if the AI skill level is likely increased significantly beyond normal human abilities, or having superman abilities; they AI troops may then hear the players approaching from beyond normal human hearing abilities.

However, when flying over the FIA base, somehow they are present and firing?

Using 1.0.0.95 ARMA Reforger update.

Work around or fix:
My personal preference is for having the AI abilities being realistic, and when in question, step down their abilities versus resorting increasing above normal human ability, as this only serves to irritating and anger players rather the player to enjoy the game. When trying to offset server load and AI alertness/abilities, probably best having this value being offset by the number of players or more accurately, the server CPU load.