Might have misunderstood you on the phone earlier, had thought you were clicking the FFwd button on screen, but the hold mouse reference above makes me wonder if you're clicking and dragging the the progress indicator across instead?
Can you remind me (and for others here) the model, Android or LibreELEC and whether it started with 17.0 for you, or 17.1/17.2/17.3 , will try and replicate set up here