I found the following bugs:
- The 6.0 logic for conjunctions didn't work when there were only `match_all`
queries in MUST/FILTER clauses as they didn't propagate the `matchAllDocs`
flag.
- Some queries still had the same issue as `BooleanQuery` used to have with
duplicate terms (see #28353), eg. `MultiPhraseQuery`.
Closes#29376