I think you’re probably right and it is randomness (and the $3 classifieds), but it’s just interesting to me in this particular case that three different sellers are all selling both the 50/2 Planar and 28/2.8 Biogon ZM lenses within the same week of each other. I used to own the Planar and Biogon at different times, and though I ultimately sold them it wasn’t because they had any kind of fault, they just weren’t for me. That may the case here too, but just curious if there might be some other pattern or trend at play. On a few other sites (Fred Miranda and some Facebook camera buy/sell groups) I’ve especially noticed a preponderance of 50/2 Planars for sale these days especially. Curious.