Bareback Help

We use our legs more riding bareback.  Perhaps your horse is sensitive to the use of leg pressure which can cause his uneasy attitude.  Also, if he's used to working from the seat and it's off balance without the saddle, this also can cause consternation in the horse.  You could take him out of the barn before mounting.  With time he should get the hang of it again.

well our weight is distributed different when we are bareback you could see if he has a sore spot, or he might feel insecure without the saddle who knows, my horse acts different while bareback but he just prances around like he's in a show cause he knows he doesnt have to do any circles,
he'll get it good luck!

My first thought is soreness.  It might be in a spot that the saddle keeps weight off of or distributes it better over the sore area.

Also - are you sure you are fully centered and balanced while riding bareback?  I know people who ride great in a saddle but seem to fall apart bareback and don't even realize it.  It could be in balance, leaning to one side or forward or back, or relying on the hands more so in his face.  Is there anyone who can take a video or lots of pics of you riding bareback so that you can see what you look like?  You might find the issue is there.

One more thought - when he was acting foolish - do you hop off?  Maybe he acted a bit out once while you were bareback and you got off which he read as a positive reinforcement and now he knows that when he acts up while you are bareback, he may get out of work a bit longer.  I know my toby would pick up those type of things and I have to be really careful when I get off him and make sure he is standing as a perfect gentleman.