It's not a problem unique to Schneider, but more likely. Strong expansion/contraction stresses in
extreme weather hot/cold-day/night fluctuations can prompt it. No big deal. Might affect resale value of a lens, but I doubt Schneideritits has ever actually affected a photograph.
Like fresh ground pepper on a juicy steak--- Schneideritis adds to the flavor! :D
You have a future in marketing/advertising (if you're not there already.) :) Schneideritis adds sizzle!
I just discovered my 305 G-Claron has flaked a bit of paint for the first time. It's at least 18 years old, so it's a bit of a surprise, I thought it was disease-free. Not that I'd sell it, but there goes some of its value. At least until the new marketing campaign goes viral.