For my work I started using a ThinkPad-L480 a few weeks ago. I immediately removed the pre-installed Windows 10 and replaced it with Ubuntu 18.04.
Apparently randomly, a few times a day, the builtin touchpad will stop responding to movements. Clicking on the touchpad still possible, as is using the buttons immediately above the touchpad. The TrackPoint (red nub on the keyboard) also still works. I have not found a way of fixing this problem, but it has so far always gone away within a few minutes.
Similarly apparently randomly, the laptop's builtin keyboard will lag. Keystrokes will be registered with a delay, or not registered at all. Sometimes the system apparently registers a key as still down even though I've released it. Similarly, this issue appears regularly (maybe once every other hour) and goes away within a few minutes.
Both these problems occur apparently regardless of what I am doing: sometimes when all I have open is a single terminal, and no other processes running. In particular, I have found no way to trigger these problems. These problems started occurring right after I got the laptop (so it should not be anything I have installed myself).
I ask about both problems in a single question, as they both have to do with the builtin input devices of the laptop, and the problems seem to tend to cluster together (if the keyboard starts acting up, I'm less surprised when the touch pad freezes). But that might just be my own confirmation bias.
How can I diagnose and solve this problem?