I have noticed some strange behavior in the picklist in 3.2.0.GA and I don't have much info to provide since we don't see any error messages in the log at all. I thought I would post what I saw anyway and will be happy to put it in jira if people feel this is enough info to open a jira issue with.
If the user selects an item in the picklist that contains a comma, such as "Microalbumin, Random Urine" in our case; the setter for the list of selected items never gets called. No error messages, nothing. The page just resets as if it was loaded for the first time. If you change the comma to something else, like a hyphen, then the setter gets called and we receive the List containing the selected items.