I think that we didn't have gremlins on our computers. We had report, which was confirmed, that timer on the world map was disappearing after 5 min of inactivity in the world map view (i'm not sure in this figure and I'm too tired to search for a thread
) and if you would try to help neighbour you were getting similar msg, something like that you can collect in lets say 13 hours. So, maybe gold mines were changing its icon to coin after 5 min or so also, and in real they were not ready for collection.
Unfortunately I didn't have gold mines in my neighbourhood to check my theory that late evening when this theory crossed my mind. And I was too tired (my real life killed me in last 10 days, and that's why I'm answering here so late and I'm very sorry for that
) and I didn't fired up my testing account. Then real life happened. And yesterday when I came back this 'timer issue' seemed resolved and now it is impossible to check my theory. I was hoping that I will be able to do that on my account on live servers, but still nothing there.
Right now this issue sounds like 'cannot reproduce' and I will mark it like that. And theoretically it would be 'duplicate' if my theory would be accurate. But it seems that we'll never know that.