Sporadically and suddenly it becomes impossible to select features in Collector, thus also preventing being able to edit them. We're using iPads and even after ensuring everything was updated it still happens. This is so frustrating and really messes with our field work, especially because we have no idea when it will happen or why. Is this a known bug or something on my end?
We had similar issues, and then realized that ESRI has moved on to Field Maps and does not support (at least not very well) Collector anymore. Try Field Maps. It's basically the same with a few upgrades.
Definitely go to Field Maps if you were using the New Collector. But Field Maps will NOT function on an ipadt that doesn't upgrade past v 13.0 IOS. Also it does run a lot better on an iPAD Pro than on any other iPAD. That's a good price jump. We've been running it on a 12.9" ipad, but the thing constantly overheats and we need to run external batery packs to get a full days work. We are going to get another 11" iPAD Pro to hopefully make it more useable and lighter to haul around all day. We have found that also sometimes for no reason the new "Snapping" capability of lines to points and points to line vertices just stops working for some reason and we have to refresh the map or log out and thne back in.
I have actually tried using it in Field Maps, both on iOS and Android, and still run into the same problem with this one feature class. I am using domains and subtypes in it so I wonder if perhaps that might have something to do with it, but I'm really at a loss.