UNION doesn't work for distributed case

[MBkkt]

Some error produced by Velox.

You can increase numWorkers here and run&debug tests:

axiom/axiom/optimizer/tests/PlanTest.cpp

Line 875 in aa6ea29

checkSame(logicalPlan, referencePlan, {.numWorkers = 1, .numDrivers = 4});

UNION ALL => AGGREGATION is same issue,
UNION ALL without aggregation is working