I think that sort of thing happens all the time. An example that comes to mind is from "California Dreamin'":

"Well, I got down on my knees And I pretend to pray"

I have never heard anyone other than the Mamas & Papas sing the words this way. I have heard folks sing "began" and I, myself, have always sung "pretended". I think the problem arose from the mixing of tenses within the sentence. It would seem that the grammatically corrected version(s) are the ones which are now in use. It is part of the neo-folk tradition, I suppose (or whatever label you wish to use).