I opened iPadOS native Legend this weekend and added several new items to a document.
Left my iPad, then went to my Windows Native Legend. The new items were not present. I went back to the iPad version and it still showed the items as present (it was now several minutes later). I could scroll and check other documents, so Legend was working. My wifi and wired internet connections were all working properly. I then force-quit the iPad Legend and waiting several seconds, then restarted iPadOS Legend. The items I had added were now gone, and had still not appeared on my Windows Legend. It appears as though the synchronizer on iPad Legend was not working, but the items were not saved locally as I would have expected.
This isn't the first time that iPhoneOS or iPadOS versions of Legend have failed to sync after being left running on those devices for long periods of time (several days).
I've suspected for some time that this causes some type of race condition where you believe you are working on your cloud data, but it isn't synching. You then go to another device and that becomes the 'current data', synch with the cloud, then when you restart the failed device instance, it synchronizes with that other data and erases your changes. This happened OFTEN on the iPhone, but this was one of the few time I saw it on the iPad.
I've decided to go back to 'force-quitting' my iPad and iOS Legends every time I finish using them.
It's been mentioned before that that Legend should not show or allow editing of a list until it is certain the data has been synched (if it is a cloud doc), and present some type of big red "UNABLE TO CONNECT TO CLOUD" if it cannot connect. Muscle memory is that if Legend loads and display my list, then it must be working. There isn't enough error trapping if the app is still running, the device is activated, and the app is shown to the user but NOT launched.