Random errors about PostGIS without using it

When I issue queries using SQuirrel, I get the following error at random whereas I do not use any Geo functions:

Originally TeiidProcessingException 'ERROR: function postgis_full_version() does not exist
Hint: No function matches the given name and argument types. You might need to add explicit type casts.
Position: 8' QueryExecutorImpl.java:2455. Enable more detailed logging to see the entire stacktrace.