I use a full update, but still have the problem, in short, I'm doing the following.
(On callback refresh)
scheduler.Resources.Clear();
foreach(Resource resource in myResources)
scheduler.Resources.Add(resource)
scheduler.DataSource = mySchedules;
scheduler.DataBind();
scheduler.Update(CallBackUpdate.Full);
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When the page is loaded for the first time this works correctly. On refresh, when the amount of resources/schedules are changed the resources aren't updated.