Hi Kuba Cole,
Unfortunately we do not have documentation on this topic yet. However, I will try to shed some light here. The meaning of this warning is the following - If you have an array field in some persistent class and change the whole array with another, change tracking will work, but if you change only one element of the array, it will not. So, to avoid this behavior, the field should be explicitly marked as "Dirty" when such operation occurs. You can use the ObjectScope.MakeDirty(object, fieldName)
method to do this when necessary. Hope that helps.
the Telerik team