All, 

I am having an issue where when I flatten an edge flange it flattens fine until I click away from the document, save and re-open the document, or try to make any changes to the document. So, pretty much when I do anything it unflattens that flange. 

Here is that last edge flange right after being created:

Then it flatten fine:

I click the adjacent open drawing and the edge flange rebends itself on the right:

If I unflatten and reflatten, the edge flange is no longer unbendable/able to be made flat. 

Does anyone have any idea where my issue is stemming from?