Yes, it has been fixed in the sense that we can indeed download 1.569 now. Though we will not be able to download 1.569 in some remote future point in time from now after the new code signing certificate will have expired again.
BUT I learn from http://portableapps.com/node/24236 (the last remark by John T. Haller dated July 14, 2010 at 10:41am in that thread that the fault isn't with the Jenkins / Winp developers at all but with the people who implemented / configured the certificate checks on our content inspection HTTP proxy server.
After reading, it sounds quite logical to me that a code signing certificate needs to be valid at the point in time the code is signed, not at the code in time I want to download or execute the code. Unless the certificate had been revoked in the meanwhile, but that doesn't seem to be the case here.
So in other words, you didn't actually fix it neither by chance nor by purpose but it's just luck that when I tried to download 1.569 yesterday that I was still within the time window of validity of your code signing certificate, despite that time window shouldn't matter at all for my download.