I have been learning how to use motions lately, so I am still a new at it and I don't have the stork, so make of this what you will
Looking at the stork in the store, it has Fly Start, Fly End and Fly Loop. If you are using a bunch of Fly Loops together, and trying to edit the last one, that seems to be what one of the problem may be. Not with the Fly Loops, but with the editing that you want to do to it.
You also seem to be having a problem between the last Fly Loop and the Fly End.
Try this - Collect Clip Fly Start, all of the Fly Loops, and the Fly End and save as one motion. Delete the Fly Start, Fly Loops, and Fly End you had and replace them with this one new clip. Now try to Edit Motion Layer.
There are other things you can try, but I can't explain them well. Sample Clip is one of them.