L.A. Times Gaffe

Today in the print version of the L.A. Times I came across the following: "For millenniums . . . " Really? That looks so wrong! But according to the dictionary.com, both "millennia" and "millenniums" are acceptable. "Millenniums" is even listed first, and as I type this, only "millennia" gets the red spell-check underline. What's next? "Syllabuses"? Sigh. Dictionary.com lists that one, too.