It appears that the mixing of Organizations and Locations in the filter suggestion drop down occurs regardless of the global organization and location. This issue also occurs outside of HTTP Proxies (like with Domains), so it seems to be a separate problem with Foreman.

The results are the same if searching with the v2 API as well. Querying https://admin:changeme@centos7-katello-devel-stable.example.com/api/http_proxies?search=location%3D+%22Default+Location%22 returns all HTTP Proxies, even the ones that don't belong to the Default Location.

It appears that the SQL query for the HTTP Proxies is missing a

AND taxable_type = 'HttpProxy'

ON "http_proxies"."id" = "taxable_taxonomies"."taxable_id"

Here is the SQL:

SELECT "http_proxies"."id" AS t0_r0, "http_proxies"."name" AS t0_r1, "http_proxies"."url" AS t0_r2, "http_proxies"."username" AS t0_r3, "http_proxies"."password" AS t0_r4, "taxonomies"."id" AS t1_r0, "taxonomies"."name" AS t1_r1, "taxonomies"."type" AS t1_r2, "taxonomies"."created_at" AS t1_r3, "taxonomies"."updated_at" AS t1_r4, "taxonomies"."ignore_types" AS t1_r5, "taxonomies"."description" AS t1_r6, "taxonomies"."label" AS t1_r7, "taxonomies"."ancestry" AS t1_r8, "taxonomies"."title" AS t1_r9, "taxonomies"."manifest_refreshed_at" AS t1_r10 FROM "http_proxies" LEFT OUTER JOIN "taxable_taxonomies" ON "taxable_taxonomies"."taxable_id" = "http_proxies"."id" AND "taxable_taxonomies"."taxable_type" = 'HttpProxy' LEFT OUTER JOIN "taxonomies" ON "taxonomies"."id" = "taxable_taxonomies"."taxonomy_id" AND "taxonomies"."type" = 'Organization' WHERE (("http_proxies"."id" IN (SELECT "http_proxies"."id" FROM         "http_proxies" 
        INNER JOIN "taxable_taxonomies" 
        ON "http_proxies"."id" = "taxable_taxonomies"."taxable_id"  
        INNER JOIN "taxonomies" 
        ON "taxable_taxonomies"."taxonomy_id" = "taxonomies"."id" 
 WHERE "taxonomies"."name" = 'Default Organization' ))) ORDER BY http_proxies.name

Adding that SQL manually fixes the issue, but I'm not sure yet why it isn't being added. The SQL to search for Domain, for example, has that extra SQL in it.