Is this happening after certain events? Like only after they eat? And how often and how long has this been going on?
It's a bit difficult to see, but it looks like the glottis may have been a bit irritated or swollen looking...
It may not be a bad idea to look into a reptile vet in your area. There doesn't seem to be any off color or excess mucus, but again it is a bit difficult to see. It could be the start of an infection or maybe an injury while feeding. A qualified vet may be able to get a better idea of what's up with an up close and personal look