11mos? Its just about time to start adding some ob to the protection,,,,,,, but maybe not,,, I think you need to trust the TD and/or helper on that. Your feeling could be exactly right, but what are they seeing? After you leave the field, you can try walking him around with the sleeve a little more, till he settles. MAybe walk him back towards the field and see if his attention goes to the field and a little less on the sleeve he has, or just the opposite, farther away till he settles that little bit. Lot of help, huh? Lol.
One problem with leaking, I think, is if it escalates to control problems. You can try really working on capping, rewarding as soon as he's silent and then building on that. It can be tough.
Is this club active? Trialing and titling dogs?