I just dropped by to say I've read this thread.
The code has been around a long time and no one has made this type of claim. The code has unit tests to ensure accuracy. Also, in testing we have used the bulk wallet in the past to generate 10,000+ addresses and tested them against other bitcoin software to ensure only good matching pairs are being generated.
Even in this claim the generated address and private key match because the address is passed into the function that creates the QR code for the bitcoin address. Meaning the complex bitcoin part of the code worked fine. So, the behavior that is claimed to be affected would be the simple code that is updating the HTML.
As a sanity check I would ask the OP to run the unit tests by placing a query string at the end of the page, please do this with the offline version you presumably downloaded.
https://www.bitaddress.org/bitaddress.org-v2.9.3-SHA1-7d47ab312789b7b3c1792e4abdb8f2d95b726d64.html?unittests=trueOP was your browser or system misbehaving in any way you could detect? Was your system low on memory or anything that might shed light on this? My questions are just speculatings.
At this moment it seems more plausible you have encountered some new malware. Easier for malware to change the text in the HTML then to swap out the QR code. PLUS the wrong bitcoin address shown in your screenshot has money on it meaning that someone else controls that key. If this were a legitimate code failure it would not produce an existing bitcoin address because a collision like that is theoretically impossible.