Welcome to the forum Bigfork.
Not sure if it is the case with the thinkware cameras, but some other brands provide a thin ( 1 mm or so ) EVA foam pad to put on the camera back side or mount to pick up any slack there.
Anything DIY you can do to tighten up / fill the gap / increase friction it it should be fine too, i would not recommend doing that with drops of CA glue, though when hardened that should fill the gap somewhat, but that kind of glue when it harden it give off fumes that can ruin lens coatings.
Maybe some tape will do it too, though not sure of durability.
Do you often take the camera off the mount ? this usually increase wear on the mount / camera bond, but they do also wear out over time, cuz i have once experienced that.
Some of us do use the strong velcro from 3M some times, the mushroom kind not the regular old hook and loop Velcro, the U1000 dont it have its GPS in the mount ? if so nixing the mount will mean no GPS.