The option for adding the date to the status bar makes mine show month/day. The only reason I can think yours is doing the opposite would be if the phone thinks it's in a country that uses day/month format more commonly. If you live in the US or Canada, it may just be a glitch. The only thing I can recommend (if I was having this problem) would be to go into Cydia, uninstall SBsettings, then reinstall. It may be a pain in the butt, but it could be the only option.