To reproduce the problem: Copy 3 actions and the order of this 3 actions is messed up, then arrange them as you want them to be, open 1 for editing save it, then the order is messed up again.
When you copy something it's doing a clone of it. This includes its order. SQL treats same orders oddly so you get weird behavior having multiple entries with the same order. When you save something we correct the same ordering so it makes more sense. Have added a bug ticket to fix the copy endpoint so it runs updateOrdering when possible, which will correct this issue.
forge.joomlapolis.com/issues/5499