I suspect that one of the features used within the Open Weather Custom Tile isn’t compatible with iOS 10.3 since it’s such an old browser at this point.
I spent some time trying to track down what could be causing the issue on iOS 10.3 for this custom tile, but it’s very hard to debug with iOS 10.3 since Apple sunset support for it, including the developer tools needed to view the errors/logging from the device.
That being said, we are in the process of updating our frontend platform and as part of this I’ve been doing deeper regression testing on older iPad devices, so I placed an order for an older Mac which should help me better test these older iPads. I can’t commit to spending a lot of time on it since it’s such an outdated device at this point, but once the test hardware comes in I’ll take another look at it.