Suspension sometimes fails with black screen

Sometimes (about 1 of 5) the suspension does not work on Librem 14. Screen goes black, leds stay on, capslock led does not change when pressed, cpu runs warm. I did not figure any other way then turn it off and on again.

It did not happen before. It may be since some Qubes update, or some Purism firmware update.

Does anyone have same problem? How can I diagnose it? Which log file could give hint?