Looking at some screenshots, it has a fancy appearance, probably it's using some hardware accelerated graphics api (D2D for example) do draw its window and controls. Ergo it does use the GPU.
However, if the issue remains when this application is minimized/hidden, it suggests it doesn't release resources as it should and still holds on to the graphics api (and the GPU) for no reason.
I'd open it with the dependency walker and see what api it uses. Running a profiling on it would give some insight as well. Then I'd have something to contoct Logitech support with.
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