from error.log
[27-Nov-2019 23:01:48 UTC] PHP Fatal error: ob_end_flush(): Cannot use output buffering in output buffering display handlers in ../teawea/wp-includes/functions.php on line 4469
– just a few of there lines in the error.log file
Running on all the latest versions as of today.
Possibly a plugin? or the Theme? Not easy to reproduce.