OS: Windows Server 2012 R2 Standard
BBP compile version: 1.1.1.1
Alright, I found the bug! You definitely were not at fault, you exploited something very interesting.
So we have alot of sigs in the chain already, probably 4000 or so, and we have 12 that are bad. Im guessing that maybe 6-12 are yours.
So whats happening is there is a piece of math in the code that tacks your CPID signature on the back of a PODC update. Since we only allow up to 3000 characters of free ascii space per Coinstake recipient, we add on more recipients (from your own address book) for space and change (change as in money owed to you if you broke a large bill in the coinstake).
So there is a funny behavior that occurs if the PODC update is between 3000 and 3100 long, the ceiling function returns like 1.01 (which gets rounded to 2), but for some reason when that happens, the change recipient (you) gets duplicated and it mangles the CPID base64 portion of the sig. This only happens for PODCs that are between 3000 and 3100. If they are 3101 or lower than 3000 they are OK.
Yours is 3100.
So anyway I am patching this now, windows is going to take hours to compile and Ill be out meeting someone soon, but Ive unit tested it and I believe its going to solve the problem globally.
Ill check in the unix version in about 15 mins, so if that helps you send it out you can grab that soon... Otherwise Ill check in windows tonight before the end of the night.
Im glad you found this, thanks!