This query works in PGAdmin and validates via the Edit query dialog in ArcGIS 10.5 however raises:
select *,ST_Z(Shape) AS "Height" from awsprod.lccgis.FLO_BUILDING_FLOOR_HEIGHTS
If I remove the all important ST_Z(Shape) AS "Height" the query works fine in the attributes.
I had a similar problem in Oracle the other day. It was related to using a function that returned value with an input value that was too long (too many string characters) for the function. So with that, I wonder if your ST_GEOMETRY might be not have z values. If you view the query's results in pgAdmin what values are being returned from ST_Z(Shape)?
Placing the double-quotes around "Height" may have forced the SELECT result set to have a column named "Height", which ArcGIS cannot "see" because it requires ANSI-conformant SQL naming. Try eliminating the double-quotes from the SELECT statement.