Visual bug my butt. The last time this has happened to me, it removed my jetpack while I was howering over a bloody pit of lava.
Well atleast you know... it's statistically highly possible, that there was some lava under me somewhere. That was in my base I jetpacked up to one of xytanks, glitched, didn't show contents. Clicked it and fell some 20 blocks. Okay, there was no lava within 20 blocks, BUT IT STARTLED ME, OKAY?