I have a ShareActionProvider together with some other options in my ActionBar. It seems however that the ShareActionProvider has problems rendering properly when first rendered
I don't think it's a bug. It's because your title changed. It was shorter ("Details" instead of "ReceiptDetail") originally, and so the system must have thought there was more room to show more action items.
Also the width of the ShareActionProvider is dynamic (it can be up to more than 2 times the normal width).
To test a thing or two, I would propose you move the share action item up to the first position, remove your temporary workaround, and see if it still occurs. You could also remove the share action item and use 3 or more conventional action items as a test.