After changing armor, elytra stops working and so does the armor bar

If i change my chest plate with an elytra, the armor bar gets stuck and my elytra doesnt work. Even if i put the armor back on, it doesnt work. This has been happening since 1.10 (or whenever elytra was released) in the picture below, I have full diamond yet it shows otherwise in the armor bar. If i change my chest plate with an elytra, the armor bar gets stuck and my elytra doesnt work. Even if i put the armor back on, it doesnt work. This has been happening since 1.10 (or whenever elytra was released) in the picture below, I have full diamond yet it shows otherwise in the armor bar.
http://imgur.com/a/QEpOd