I’ll bet this has something to do with the Referer header. Iirc DDG used to always use this forwarding method so that you don’t leak your search phrase to the site you’re going to. I wonder if now there’s a way for DDG to instruct Firefox to omit the Referer header (or if DDG detects that you have Firefox configured to not send the header), but that Edge still sends the Referer header?
I’ve switched off the setting and tested with web debugger. Apparently MS Edge respects the “referrer-policy: origin” HTTP header i.e. it only sends “Referer: https://duckduckgo.com/” without query strings attached.
However, duckduckgo treat MS Edge the same way as IE, i.e. it doesn’t believe it’s not an older browser. I’ve wrote their support, hopefully they’ll fix soon. Meanwhile, I’ve switched off “Redirect (when necessary)” setting and it works OK on this PC.
