The following string wasn't important when updating from 8.7 to 8.8
https://localize.drupal.org/translate/languages/de/translate?sid=2586686
The reason is, that the malformed HTML routine of drupal doesn't allow <div>, currently. this needs to be patched in core.
as a quick fix this string shouldn't get noticed by t();
See referenced issue There are more modules affected by this bug.
Quick fix:
Deleted the string from l.d.o so there will be no error when updating translations. by now the module isn't translated to 100 % anymore, because of that.
Needs work
10.0
Code
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It's likely this issue predates Contrib.social: some issue and comment data are missing.