The mediawiki/core Selenium spec shows page creation in tests/selenium/specs/recentchanges.js can fail when it is running concurrently with another test doing modifications or creating pages. Itdoes an edit then look up the first entry in the recent change:

async () => ( await RecentChangesPage.titles[ 0 ].getText() ) === name

Which might never be true if in between another test did an update. That leads to a test timeout waiting for the condition to be true.

I had the issue on an unrelated change https://gerrit.wikimedia.org/r/c/mediawiki/core/+/842391/