Interesting. Installed Win10 into the M.2_1 drive a couple of weeks ago on my ASUS MB because I didn't have a CPU that could see it when I first built the machine. Then I reinstalled Firefox and transferred bookmarks. Did the majority of the settings manually to keep it clean.
Today the link is working with the same settings so I have no explanation for the glitch. Oh, and yes, the page address is the same today as it was in the OP.