If you have levitation you can still fly downwards with an Elytra

So I was recently Endbusting with a friend and accidentally hit the space bar and I started two go downwards while still having the levitation effect and at first I didn't know what had made me go down but then I tried the space bar again and that did it 

So it's really useful though when actually playing but I assume its a bug because that doesn't seem right I think it should be at the minimum that maybe you just stay in mid-air instead of going down

I haven't tested this Bug in other versions yet because I just found out about it today