(regression) Search Builder syntax error when "Groups" "is empty"
This is new in 5.13.0 and was reported here. It's easy to replicate from the screenshot: https://civicrm.stackexchange.com/questions/31083/in-civicrm-rel-5-14-the-search-builder-no-longer-provides-some-results
This regression occurs as a result of PR 13603 which is intended to fix #726 (closed).