I thought that any change like that would affect users upon their *next* login. For users that were already logged on when the change was made, don't think Moodle attempts to kill their session and re-establish via session files.
There is a line in config-dist.php for extending the time outs for locks - guess that shows recommended default. Otherwise, it's 90?
I run CentOS 6 and 7 servers ... don't think I've ever seen the error before but then again, usage of your system and those that I admin probably not the same.
Let's give a day?
'spirit of sharing', Ken