PostGIS ERROR: operator does not exist: postgis.geometry @ geometry
Sounds to me like you have PostGIS installed in your database more than once, possibly once via CREATE EXTENSION and again via a load script, or from a dump.

The hint is that:

PG::UndefinedFunction: ERROR: operator does not exist: postgis.geometry @ geometry


mentions the schema qualifier postgis.geometry for one operand, and omits it for another. I'd say you have two copies of the the geometry type in different schemas, probably public and postgis.