Verified on prev.test (v5.14.2-rc1) that no crashes occur when searching using the date-picker operators ON, BEFORE, AFTER. Tested on Chrome, iOS, Android. Also spot-checked other auto-complete search terms IN and FROM, and tested combinations of them (and also basic text search) as well.
Closing. Verified release tests exist for this; the issue wasn't caught because we don't do full manual release testing on dot-releases.