The Division 2 is struggling with a number of bugs that the community is eagerly sniffing out. One particular problem that keeps popping up is the disappearing turret bug, which renders your deployed turret skill inoperable and inaccessible from time to time.
The Division 2 turret problem seems to appear to a wide array of players, in a wide array of different combat situations, and give the fact that it can and should be a lifesaver in certain situations, this development is rather problematic.
The Division 2 disappearing turret bug manifests itself in the following manner: first, player deploys the turret (or drone) on a piece of cover, then the skill functions normally for about 3 seconds or so, and then the item outright disappears, only for the 15-second cooldown to kick in shortly afterwards. Clearly, skill items have a tendency to stop functioning at random, and this is a major issue.
In some extreme cases, the deployable stops working permanently, with no cooldown showing up at all. Some players have noticed that the problem is particularly prevalent in geometrically-complex areas, so if you can avoid placing your deployable turret in a bunch of clutter, this might alleviate the issue somewhat.
The supply drop glitch is another Division 2 issue that Ubisoft is having trouble with. Granted, this is all par the course for such an ambitious game, but it does kill the hype somewhat to see such an assortment of bugs piling up.