It seems that there are bug/bugs in Mediawiki 1.31 cache system. Where sometimes page will show totally different page than it currently is, and with page refresh/purge. the random content may change to other random page or change back.
Moreover, some times that page content will change to totally different template contents after submit, which made many edit lost and cause editors mad.
How to debug? Is anyone have similar bug like us in MW 1.31 or earlier version?