If the problem still persists, in Safe Mode swap out the mouse with a new one (different brand/model if possible) and repeat #1 and #2.
If the problem persists, in Safe Mode try plugging them into a different hub on the computer, if available, so if they were in the back then try them in the front.
In Safe Mode, I would unplug all but the keyboard and mouse, plug those two directly into the computer to see what the results are.
Not saying that's the case, but something to consider. I've encountered some early USB 3 ports on some motherboards that had software and drivers that installed and there was software that ran on startup.
Have you tried Safe Mode to rule out any joke/malicious programs?.
Do you have another one around that you can swap it out with to see if there is a problem with the hub itself?.
Is the user trying to charge any phone or other devices through this hub?.