Time in calendar applet in panel loops

[Ctulhu]

Hi all

I am running Mint 19.3 (fresh install) and yesterday the time in the calendar applet in panel stopped working. I set it to network time (Pacific Standard Daylight Time) and

sudo hwclock

shows that the hardware clock is working fine, but the time now loops through 08:04 all the time: the second 08:59 is reached it goes back to 08:00. (My other laptop, also with Mint 19.3 (updated from 19.2) works fine. I tried restarting Cinnamon, nothing, I tried re-syncing via ntpd but I can't imagine it's that since hwclock works - any thoughts?

Thanks,
C

[Ctulhu]

Update: I haven't done anything to the laptop but now the date/time applet is looping through 09:04 although hwclock is still showing the correct time.

[Ctulhu]

Update: I haven't done anything to the laptop but now the date/time applet is looping through 10:04 although hwclock is still showing the correct time. It seems as if the hour is always that of the correct time, but the minute is 'frozen' ...