sqlalchemy.exc.ProgrammingError: (psycopg2.errors.UndefinedTable) missing FROM-clause entry for table "anon_1" #504

sqlalchemy.exc.ProgrammingError: (psycopg2.errors.UndefinedTable) missing FROM-clause entry for table "anon_1"

from my line of code

result = browser.aggregate(cell,drilldown=['client'])

cubes==1.0.1
Flask==0.10.1
Flask-SQLAlchemy==2.0

are my related requirement.txt entries. I am in the middle of project upgrade of a legacy app where cubes used as main reporting engine.

The code has been running quite a long period without any issues.

Any hint please?