Hey there,
I have now updated again to 4.7.7 and everything works fine now. We use openstreetmap and I have seen there strange behaviour before: Sometimes the openstreetmap doesn't load and the page needs endless to view the events page. But the main time it works. I think its because of sometimes the openstreetmap api didn't respond but I am not 100% sure what causes it. I will have an eye on it 🙂