Hibernate Search 5 was not very strict, it used to accept any field even if it didn’t know about it (and then it would behave strangely, which is why we stopped doing that in 6).
Also, Hibernate Search 5 would not handle dynamic fields explicitly, so most likely you were relying on Elasticsearch’s ability to automatically add fields it didn’t know about. And Elasticsearch adds a keyword sub-field by default in that case.
Correct.
EDIT: though if you don’t remove keyword, you’ll also need to find a way to define the keyword sub-field on archetype.archetypeId, opsgenie.uuid, etc. Your current Hibernate Search mapping doesn’t define the keyword sub-field, and due to how Hibernate Search 6 works, Elasticsearch won’t add it automatically like it did with Hibernate Search 5. Changing that might prove a bit difficult.
So to sum up, you’re better off removing .keyword 