If you have multiple facet summaries, each with different facet selections, the facet config from only the first one is applied to the facet list for all of them. This means that a summary with no facets effectively disables the facets on subsequent facets.
- Create a summary with no facets and another with facets and places blocks in that order.
- The second summary will be missing facets.
The problem is that DefaultFacetsSummaryManager->getFacets stores the facets for the facetsource but filters by the specific summary facets. Unfortunately subsequent method calls use this list and it isn't updated because it is is only populated on the first run.
I propose moving the summary-specific filtering to a later point when it is building the facet summary.
Needs review
2.0
Code
I should also point out that this didn't seem to be a problem until I upgraded to Drupal 10.