I can't be sure, but I think the reddit threads seem to be USA/Canada focussed. I've not seen anyone specifically mention European or other countries having the shorter 1.8m cable terminating in a 3.5mm plug with screw-on 6.35mm adaptor.
Oddly Sennheiser's own website has an image of the old 3m cable ending in 1/4" with a short 1/4" - 1/8" adaptor cable, accompanied with the new cable text:
View attachment 258564
I feel uneasy about anecdotal reports of folks comparing old-style against the new-variant they just bought and discovering significant enough sonic differences to return the new short-cable ones. Hmm.
It's a known phenomenon that pad changes, even newer/fresher vs. worn can make a difference. Perhaps it's just the pads making the difference and not a cut-price driver? Dare I sound like I am speculating and throwing petrol onto a candle flame.