Divergence between Planning Board and Jira database

I've been doing some SQL queries to the JIRA database regarding issues in closed sprints - and I encountered some problems because the SQL results do not match to what's displayed in JIRA!
In SQL database some issues already belong to a certain sprint, but when you click on one of those issues (which seem to have issue type “Sub-Task” only) by selecting “View on Rapid Board”, JIRA only refers to sprint backlog, but doesn’t show any of those issues there.
Maybe this issue is in relation to @GHS-5440.