List will not stay sorted - always resorts to manual

Last week I posted that a list was sorting properly in the back end, but not in the control. That was not correct. What I have actually found is that when I sort the list alphabetically in the back end, it appears to sort, but then when I navigate away from the list in the back end and come back to it, the sorting has reverted to manual. I am using Sitefinity 5.0.2860.0. The list will not stay sorted.