Originally Posted by TonyR
Yes, you do have an advantage having watched it all more recently. But I'm still not 100% sold on the joints not being in his pocket triggering the connection like that. But I'll go with it.
I'd have a problem if it seemed out of character for Jesse, but it's been well established that Jesse is intelligent enough to make the deduction.
The scenes where Huell lifts both the ricin cigarette and the joint are in the show. The joint was a little more obvious, but both times you'd miss it if you weren't paying attention. If you look for it, and given it happened to Jesse twice, it's not implausible that he figured it out.