Completed repeating task on both Mac & iPhone, now 2 new tasks

First day using Omnifocus, trying it on both Mac and iPhone. The Mac is Yosemite, latest Omnifocus, connected through university ethernet. The iPhone is latest Omnifocus, iOS8.1 connected through 4G.

Yesterday I created a repeating task (every 2 weeks) due today. Today, I checked the task as completed on my Mac. Half an hour later, I grabbed my phone, went to the notification center widget and checked some tasks as completed. The repeating task was also visible in the widget, so I made sure to check it as completed on my phone too.

Later in the day, I fired up Omnifocus on Mac to get an overview of all my todo’s. To my surprise, in 4 weeks, i now had 2 repeating tasks. These tasks had a due time half an hour from each other.

Migrating from Things, I immediately noticed that Omnifocus sync was much slower than Things, but is it really This bad? I complete the same repeating task on two machines since Omnifocus doesnt sync quick enough, and then the program isn’t smart enough to understand it was the same task so it creates 2 new repeating tasks?