I have noticed that 2 of my geckos do this weird thing where they are moving fine in empty space but then they jerk their head back as if something is there. It is like they move forwards and then backwards forwards and then backwards. Is this a sign of Enigma Syndrome. The geckos do not have enigma or white and yellow. This also usually only happens if they are under a little stress. Thanks. (if you want a video I can do that aswell.)