If you leave the game running but not selected for long enough (however long that is?) and go back to get your hourly tribute, the gold coins icon (on your home kingdom) sometimes acts weird. It doesn’t smoothly grow and shrink, it goes from small to large to small rather quickly in an unsettling jumpy fashion.
Can be reproduced (frequently but not guaranteed) by tabbing out on the Steam Client and coming back after a while. 30-60 minutes should do it, a couple hours would be more likely. I think the same thing can happen on my iOS version but I don’t play it enough to quantify that.
This has been happening for … months? Just thought it wasn’t high priority.