PostGIS ST_Intersects GeometryCollection

Spatial relation operators do not work on geometry collections by design, as inherited from JTS.

Try using ST_CollectionHomogenize, which will return a regular geometry, if possible. Or ST_CollectionExtract to specify a geometry type.

According to the PostGIS documentation for the ST_Intersects function, the PostGIS version "2.5.0 Supports GEOMETRYCOLLECTION".

It may be good to note that, the PostGIS version 2.5.0 release news states that "this release will work for PostgreSQL 9.4 and above but to take full advantage of what PostGIS 2.5 offers, you should be running PostgreSQL 11beta4+ and GEOS 3.7.0".