Hi @evici,
I was facing similar problem in my OJS instance. (3.4.0.1)
I found that it was caused by the site’s search functionality that uses the classes/search/ArticleSearchDAO.php that has a cast that causes this block of the database
JOIN issues i ON (CAST(i.issue_id AS CHAR(20)) = ps.setting_value AND i.journal_id = s.context_id)
To outline this, I removed the CAST:
JOIN issues i ON (CAST(i.issue_id AS CHAR(20)) = ps.setting_value AND i.journal_id = s.context_id)
This solved the problem for me. I hope it can help you too.
The history here