On further analysis: the ONE difference between the split starter is the jugs. One was a wine jug used for lots of starters before, the other is an apple juice jug I thought had been used before but may be a recent aquire. I'm thinking I didn't leave it in the PBW long enough before the starsan and that may have left residue.
On closer look, that jugs looks a little redder (could just be less yeast flocculating), and most damning is that it smells kinda cidery. The wine jug smells kinda malty. So, what would grow in old cider residue?
I think ill cobble up another clean jug and split the "good one".