Dear Support,
I use in default mode, no custom field, no filter, no tab, etc, just input Epic and Task on Backlog and it shows automatically on Timeline.
But somehow, some issue is missing in Backlog, but still shows on Timeline:

89 issues on Timeline but only 53 issues shows on Backlog, trying to follow another user's community questions but no luck so far.
This is column and statuses setting and still in default setting:

This is default custom filters:

Any advice?
Thank you