18.04 – The mouse and keyboard are locked

From time to time, the mouse and keyboard will stop working for about 1 second.

If I typed to solve this problem, the key is printed 20 times after being thawed.

If I used the mouse, the action during this time is ignored.

It's a former Dell Latitude (E6530) but with a new SSD.

I have tested the processor and no errors have been reported.
I have tested the ram with memtest 4.3.7 – no mistake.
I also tested it with memtest 5.01 singlecore – no error, though i force the multi-threading on startup, it hangs at test # 7, passes 21%, tests 81% but does not report no mistake.

If it was a ram problem, there should be more than a freeze of 1, I guess …

Help appreciated 🙂