After upgrading to Gateway 11.1 we see the following kinds of messages generated to stdout after rebooting the server:
Data hash table of /run/log/journal/####/system.journal has a fill level at 75.1 (3273 of 4359 items, 2510848 file size, 767 bytes per hash table item), suggesting rotation.
/run/log/journal/####/system.journal: Journal header limits reached or header out-of-date, rotating.
CA API Gateway 11.1
The journalctl messages seen are due to an update within the systemd package as these particular messages have gone from a 'debug' level to a 'info' level which is why we now see this situation occurring.
This is addressed within version 255 of the systemd package. We will provide an update of this package within a future gateway 11.1 Monthly Platform Patch.