Stray U.S. Marriage?

The Pennsylvania, Philadelphia Marriage Indexes and the FamilySearch Pilot Website both have a reference to a 19th Century marriage of Robert Dunlap McIlhagga to Lizzie Jane Patterson. The US names Robert and the FS Pilot names Lizzie and the date 5th January 1894. 'Dunlap' is clearly an American version of Dunlop and the only Robert Dunlop McIlhagga of an age to marry in 1894 was born 3rd August 1866 at Castlequarter, County Antrim. He would have been 28. However, we have no evidence that he went abroad and we have a marriage for him on 13th February 1900 in Ballymoney, County Antrim, to Annie Thom(p)son, who subsequently had eight children by him. Robert may of course have married twice and his first wife could have died, causing him to return to Ireland. At his marriage to Annie he would have been 34, somewhat old we may think for a first marriage.

We do know that Robert's older brother James emigrated to the New World, settling in Canada, though he did get married in the USA, in Wayne, Detroit, Michigan. It is quite feasible that Robert joined his brother in the States, married there also, and sometime between 1894 and 1900 returned to Ireland.