Mail Body not displayed [fixed by reboot]

Since a few days the body of any mail is not visible anymore. If I change the number of previewed lines, I can see, that the body is available, but when looking at the mail itself, no content is visible except attachments.

I suspect some updates of a bunch of apps to cause the issue, but don’t have any idea, how to narrow down to the real cause and to fix the problem.
Any help appreciated.
version is 6.202 on moto g(6) plus with android v9 PPW29.116-20-28

from a similar issue I found the solution:
reboot the device.