i have a similar issue with my beardie but before i go on let me answer the above question and ill answer mine all together probably just opening for convoersation...
but ive had about 4 dragons in my time so far and have noticed when in the younger dragons will open there mouth and puff out beard or head bob when claiming territory, and this is also commen in tanks that house multiple beardies that have been together for awhile they will fight for
UVB light, sooo that being said if u see your beardie head bobbing and trying desperatly to get as close to the
UVB light as possible it might be time to change the bulb. UVB 18" florescent bulb from pet supplies plus was $21.00 great buy and they had the smaller bulbs for $17.00 so i purchased a spare, what bothered me was my dragon is a little over 2.5years old at 18.5" his name is Gator, now i just got him a new light but he seems to still be head bobbing alot he even lunged at my finger when i was trying to clean his cage,
i also want to add that cage size is not the issue in my situation i have a 3'x2'x2' wooden plexy glass cage nicely set up,
he cant complain about food he gets his greens regularly there might be a few days i cant offer him greens but he hardly ever eats them, maybe he will eat more greens i got him a new light? he eats a mix of LARGE juicy crickets and super plump dubai roaches, and i can hand feed him without him biting me but still he tried biting me after i gave him new light ... such an unforgiving lil ... anyway i wont go there i think i need to show him sum more personal 1v1 time to temper him more
thats the answer to the above post if you have done everything you can possibly do for your beardie health wise , meaning
*clean the cage
*fresh water
*fresh greens
*new lights
* full tummy
* temperature and hummidity is right
well lizard proof your room and let him out for a lil bit spend some personal time with it about 3 times a week for a month and he will come arround >-{[(DO NOT PUT BEARDIE ON BED OR HIGH SURFACE)]}-<
accidents do happen and dragons can get spooked and run and ... well your dragon seals its own fate.