false indication of free iPhone storage

Hi everyone.

I discovered a problem with the indication of my available iPhone storage (preferences - general - usage).

I have around 3GB of free storage. Instacast downloaded two podcasts which were around 1GB each so that i ended up with a couple of hundred MB. After watching/deleting the podcasts from instacast, the overall free storage didn't increase at it should have. Instacast, however, doesn't show up with more than the size of the app itself (the GBs of the podcasts are gone).

The iPhone thinks that the storage is nearly full. When Instacast wanted to download another episode this week, the notification came up that I was running out of storage.

After rebooting the device everything was back to normal and the storage was as it should be.

Anybody else experienced this behavious unter iOS 7?

Thanks in advance!