Contributors simultaneous edits

Dear iTunes U users,

In a course involving several contributors, we frequently encounter saving problems with an error message saying that another contributor was editing the course before I saved it. It seems somewhat strange that contributours can't work together and at the same time on a lesson, while collaboration is the purpose of the platform. This happens mainly on iOS with contributors working on iPads. Is there something we do wrong?

General info:

ipad mini and iPad Air 2

ios 9.2.1, iTunes U 3.1

would like to post a picture of the error message but this form is not fully iOS compatible... ;-)