After a bit of a Googling session, this seems to be a common problem.
Sarcastic bit
In the best tradition of software companies the world over, it's "not a problem with the browser" although a cache refresh ans browser reset often seems to clear it ...
Obviously it can't be a browser issue, as it only seems to affect Safari ...
End of sarcastic bit

From the miniscule amount of technical posts, it appears to be an issue with the browser cache holding out of date meta redirect/refresh info.
Hopefully that'll help a few people sort it out.