Washed Merino wool comes out a little sulfury

[Aberneth]

I bought a lovely Merino Wool pullover while I was at the coast a few weeks ago. After handwashing it with sweater soap in cold water and flat drying it over an air conditioning vent, it smells a little bit sulfury and a little bit like, well, wet wool, even though it is bone dry. I haven't had this problem with any other merino wool garments, or any wool garments in general. I wash all of them with the same soap. Thoughts on what's causing this, or a cure, gents?