With a high rate of frequency, I've noticed that the Klingon researcher at base camp, who crafts items out of those Borg crafting materials you get from Drone loot simply beams out at random. While talking to him and in the middle of crafting he'll just... beam out to god knows where for no reason. I've had to wait 5-15 minutes for him to come back just so I can craft one of those better remodulators for a boff.
I've never seen the Fed researcher beam out randomly, just the KDF one.
Unless this is intentionally designed to be extremely obnoxious, I think that should be fixed.