Sites using OPAC_SEARCH_LIMIT to restrict searches to a branch are still getting results from ALL branches when following a hotlinked search from the detailed record display, for example linked searches on the author or subject. For example, on a site where the branch only owns one book by "Dumbledore, Albus", when you search for "dumbledore", you get one hit, and Koha displays the detailed record. However, if you then click on the linked author name, the new search will retrieve ALL records with au:"Dumbledore, Albus", regardless of branch. You should only get back the same record. Presumably if a site goes through the trouble to limit searches to a branch, they would want ALL searches limited to that branch. Note that this bug appears in both 3.14.x and 3.16.x.
This is still an issue in 3.22. See notes in bug 17632.
*** Bug 17632 has been marked as a duplicate of this bug. ***