Reminders doesn't update if i modify it on my offline iPhone.

Hello, i'll explain you my problem. When i'm at home and add something in reminders on iPhone, iCal on my mac automatically refreshes and shows these reminders. But if i add anything in reminders on iPhone when i'm at work, (i don't use internet connection at work), then i come back home and open reminders so it can sync with iCal and iCloud, it won't. The checked or new reminders are not shown up in my ical neither icloud. The only thing i can do to update it is add another reminder or check/uncheck one and it will update both, ical and icloud.

Is that a known bug?