The mod Endgame Combat (https://mods.factorio.com/mod/EndgameCombat) adds a research that upgrades the range of turrets, which replaces all turrets on the map with a new entity.

So "Gun Turret" entity becomes "Gun Turret [Range Boost 2]", this applies to all turrets.

As a result, automatic fill no longer recognizes these turrets and they don't autofilled.

What's interesting about that mod, is that it doesn't generate an "on_built_entity" when those turrets are placed. I will have to delve further into that mod to see what can be done.

Ah, I see, he usurps the on_built_entity and doesn't pass the event on. I would suggest requesting that the mod author add autofill capability in this case.

Roger that, I'll go inform the author add the compatibility.