Unusual Bird: Baltimore Oriole With Red Color Variation

Adult male Baltimore Oriole, with Summer Tanager red on his upper breast, showed up on Halloween, wearing his costume. As of today, he has been seen, intermittently, for ten days, with, at least four other Baltimore Orioles, at jelly and suet feeders. I’ve only been able to find, one research pdf with similar color variations on a Baltimore Oriole. https://www.aba.org/birding/v39n5p62.pdf, I would like to know if Cornell has any more data, on this. I was not able to find anything on the different Cornell web sites, including Birds of North America, online. At least, I will be able to tell him apart from the others!