I also noticed that repeating error message after I did an apt update/upgrade. It took several minutes until the system gave up and booted into the greater. Having logged in I wasn’t able to flash the firmware - even when using the " --no-safety-check" option (…voltage too low - or so). Also systemd used quite a lot cpu power in that state and the display was flickering.
I then booted from SD-card, flashed keyboard and sc-fw by executing fwupdmgr update - and everything worked fine from then on. Pocket booted normaly.