Since this is the only way to enter contacts, it's a blocker.
https://XXX.wikimedia.org/civicrm/ajax/checkemail?noemail=1&context=activity_target&name=awight
Returns a json list containing items like, {"name":null,"id":"9366220"}. The results are correct, but name should not be null. The null name breaks the autocomplete display, so nothing useful happens.