How to troubleshoot collapsed field indicators not showing?

[Deleted user]

We have a number of custom fields with checkboxes, which usually display in a ticket with a counter alongside and 3 small leftpointing arrows (or an ellipsis) to indicate that more values are selected in the field than what you can see. 

I've just discovered that one of our users (on Safari) doesn't see these indicators. Huge problem as we now realise work has been missed because field values have been ignored.

How do I go about troubleshooting what's causing this?

After editing a field and returning to normal view the indicators appear. 

[Deleted user]

And I've just had it happen to myself on Chrome. So I guess it isn't browser specific.

Ellipsis wasn't there on first opening the ticket, refreshing didn't make it appear. I had to click in the field then out again before it showed.