That is so funny that you post that. I posted a message a few weeks back on this board saying the same thing--that soy lecithin gave me major chelation symptoms.
At the time I was already a couple of months into the Cutler protocol with DMSA. I started taking a tablespoon of lecithin in the morning and evening with some water. After a few days, I felt that unmistakable 'nutty' feeling of brain chelation, like my brain was going out of control. It scared me, but I decided to soldier on with it for a few more days. Sure enough, the chelation symptoms disappeared. But like you said, I noticed very obvious symptoms that the lecithin was having some effect on my brain, and specifically the mercury in it.