I'm using Sitecore instance 9.1, Solar 7.2.1, and SXA 1.8.
I was checking "Search" logs and found below ERROR entry.
5012 12:49:26 INFO Solr Query - ?q=((query:(self) AND _path:(71a2055091824473b4739f0f0371f665)) AND _language:(en))&rows=100&fl=_group,_uniqueid,_datasource&fq=_indexname:(sitecore_sxa_master_index)&wt=xml
5012 12:49:26 ERROR Solr Error : ["undefined field query"] - Query attempted: [((query:(self) AND _path:(71a2055091824473b4739f0f0371f665)) AND _language:(en))]
I understand why this query is failing. BUT, I don't know which component is firing this query , in order for me to edit or stop.
Any Clues ??
Have you tried searching for the item id being referenced in the query and then checking which items refer to it (using links button).
To do this, go to desktop and paste "71a20550-9182-4473-b473-9f0f0371f665" into the search box (bottom right).
If the ID matches an item in the master DB then it will find it automatically (no need to press enter).
Go to that item and look for "Links" button (think it's in review tab?)