https://www.mangaupdates.com/series/gspjf4a/shoowa-eros-manga-collection

This series should be shown in below search result. But unfortunately it is not there.

https://www.mangaupdates.com/series?genres=adult&perpage=100&year=2001&page=3&letter=S

But show in below one

https://www.mangaupdates.com/series?genres=adult&perpage=100&year=2001&page=25

Maybe missing FTS for a few series. Correct me if I am doing anything wrong. Thanks.

I found another 2 with same problem -

https://www.mangaupdates.com/series/iayc9b6/lost-reason-let-s-have-sex-as-soon-as-we-meet

https://www.mangaupdates.com/series/jxpvew9/seiki-tensou-hanareta-tokoro-kara-yarimakuri