Synchronization with iPhone iOS

So I've noticed for some time that the iPhone app reaches a point where it no longer updates. Even though synchronization works across iPad OS and Mac OS--I use five devices during the course of a teaching day--the iPhone app of iDoceo is inconsistent and, once that occurs, it will no longer update. The rotary symbol doesn't appear any longer and no green checkmark ever appears, even though synchronization is enabled and the cloud images still appear in the class listing view.

For instance, the tab in THIS WEEK, where I collate all assignments and assessments for the given week, has a green column ("Zero Draft") that is completely filled out in each cell on every device EXCEPT the iPhone where all cells appear empty. No amount of waiting for an update will produce a change either, Synchronization is enabled on all devices. They are all connected to the same wifi network. I have plenty of space available on iCloud.

The potential to overwrite more recent files makes me hesitate in using the iPhone version without really inspecting the update first before recording new assessments. I suspect the problem is with iCloud, but for me, it's a real problem.