"maximum of 3 levels of Query over Query tables only allowed" when saving 3rd level query

"maximum of 3 levels of Query over Query tables only allowed" when saving 3rd level query

I am getting the mentioned error when trying to save a Query Table that's 3 levels deep.

My setup:

Table A is an actual table, created importing CSV data

Table B is created with:
  1. select extract( YEAR_MONTH FROM "date") AS "ym",site_id, count(1) as t from page_views group by extract( YEAR_MONTH FROM "date"), site_id

Table C (the one that breaks when saving) is:
  1. select * from "Table C" where t >= 3
Actually the only reason I have Table B is because I can't use the "t" column in the WHERE clause.