high cpu load on a iPhone 4 using iCloud services

As the subject says, whenever I activate different iCloud services (calenders, notes, reminders, etc.) on my iPhone 4 (6.1.3) the cpu load goes up to 50 to 100%. On my iPad 3 everything is fine with the same configuration. I am aware of that 6.1.3 bug (battery draining) and I executed the workaround already, but nothing did change. Anybody with a confirmation on that?