I’ve noticed this mostly with golden tickets, but often notification items appear in the feed with ‘clear’ button beside them rather than the ‘x’ button. Touching ‘clear’ fails to do anything. The only way I’ve found to get back to ‘x’ is to close the app (with an upswipe) and restart it. Then all items have an ‘x’ button which turns to ‘clear’ when tapped and then clears out when tapped again.
It is intermittent in that I can have two golden ticket notifications, one with ‘x’ beside it another with ‘clear’ beside it.