It's discussed throughout the thread. A simple answer will suffice, but feel free to move this if need be.
You've piqued my curiosity on this one, because I've never seen an issue with this lens --
Searching through this thread, I found 2 instances related to "purple" or "pf": Post #92 on page 5, where it is said this lens has "more pf in the highlights than the Oly 60mm macro" (which makes sense) and notes "especially on an Oly body" and post #216, page 11, where this lens is said to have "half" the purple fringing fo the Nocticron. So if that's any indication, I think it is a low pf-lens.
Searching for internet reviews, pf seems again to be a near non-issue:
Lenstip, as an example, reports very low CA with this lens.
Imaging Resource reports the same. (same with
Photography Blog and
ePhotozine) Only
Cameralabs reports pf that I've found, but of a kind I have never personally seen in this lens, and makes me wonder what lens Gordon was actually testing.
Personally, I have not felt it exhibited any kind of pf issue in my work with this lens. I HAVE had issues with the PL25/1.4, as an example. But not this lens.
I went through the my keepers I have in LR from this lens, and spectral highlights generally look like this (shot in RAW with all adjustments removed from LR).
Hope this all helps in your decision. As you might gather, I am a big fan of the 42.5/1.7!
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