This php74 build (Gerrit change) and this php81 build (Gerrit change) failed with similar errors:
php74
SUMMARY: ✔ 1787 tests completed ℹ 13 tests skipped ✖ 6 tests failed FAILED TESTS: testrunner ✖ beforeEach Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment ✖ afterEach Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment ✖ Loader status Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment ✖ assert.htmlEqual Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment testrunner > testrunner-nested-hooks ✖ beforeEach Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment testrunner-next ✖ afterEach Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment
php81
SUMMARY: ✔ 1775 tests completed ℹ 13 tests skipped ✖ 18 tests failed FAILED TESTS: testrunner ✖ beforeEach Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment ✖ afterEach Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment ✖ Loader status Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment ✖ assert.htmlEqual Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment testrunner > testrunner-nested-hooks ✖ beforeEach Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment testrunner-next ✖ afterEach Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment ext.templateData ✖ Validation tools Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment ✖ TemplateData model Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment ✖ TemplateData sourceHandler with maps Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment ✖ TemplateData sourceHandler failure Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment ✖ TemplateData sourceHandler adding default format Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment ✖ Duplicate parameter names Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment ✖ safesubst: hack with an unnamed parameter Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment ext.translate.parsers ✖ -- External links Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment ext.uls ✖ Initial check Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment ✖ Custom langdb Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment ✖ User preferences Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment ✖ Common languages Chrome Headless 90.0.4430.212 (Linux x86_64) global failure: Unfinished AJAX requests Expected: [] Actual: [ "Some pending requests bypassed ajaxSend() and are missing details" ] newMwEnvironment
It doesn’t seem to happen all the time, but this seems frequent enough to be concerning.