Changing the name of the keyword should not affect the query failures, but it did.
Can you reproduce that from scratch and provide a full recreation script as described in About the Elasticsearch category. It will help to better understand what you are doing. Please, try to keep the example as simple as possible.
A full reproduction script will help readers to understand, reproduce and if needed fix your problem.
Keyword aggregations are much slower than before (UNSOLVED)
"size": 1000000 This is bad IMO.