Hi there, I'm having a weird issue. I've set up a new board, but when I add child issues to either Epics or Tasks, they initially show up, but if I click off the Epic or refresh the page, they disappear from the preview.
They still display in the Timeline (when it comes to tasks), but not in the preview:

If I open the Epic or the Task directly in a new window, the child tasks are also hidden, so it's not limited just to the Timeline preview:

If I add a new Task or Subtask, the list will display again:

However, if I refresh or click off then back onto the Task, the child issues vanish. They're still present and can be searched for, but don't display on the parent ticket:

It's only happening in new boards, though - I have two other boards, one on the same user, which is displaying normally:

And another separate user account I use for work:

These other boards both display fine, so I'm confused as to what the issue might be with this new board...
I've tried deleting and creating a new board, to see if it was a random issue, but this same issue occurs on any new software project board (team managed) I set up.