Frank Lautenberg’s team got caught off guard yesterday by some major endorsements for Rob Andrews in Middlesex County, where there is a serious move afoot to essentially rescind the party organization’s endorsement of the incumbent and have both candidates run in an open primary. Now that the Lautenberg operation has had a chance to focus on Middlesex, there are reports that some of the local officials who had been expected to support Andrews are now wavering – including Edison Mayor Jun Choi.