Bass Guitar String count search not returning all results

[Pedalnetics]

If I go to bass guitars for sale, search with no keywords, and just search for Strings:6, it returns ~74 results:

=126&c[thread_field_id_strings]=strings&c[thread_field_value_strings][0]=LIKE&c[thread_field_value_strings][1]=%25six%25"]Search Results | TalkBass.com

However, here is a link for a bass, with its Strings field set to 6, that doesnt appear to be in any of those 74 results:

For Sale - Ibanez BTB 1406 VNF Make Offer