Ahoy Port Manager, we are sorry to hear about the issue and that it also affects your event!
We can assure you that we are still doing our best to further investigate the cause, but so far it seems that the older iOS devices with ram 2GB (3GB is recommended RAM for smooth gameplay) are taking a toll on the graphics, thus creating the "black spots, holes and artifacts"- but we are still on the case! 🔎
We will be further updating about the changes or new findings HERE - until then we are really grateful for your further information and patience! 🤞