iOS Badge cannot be set to zero in some situations

Slightly strange chain of events, but I see a problem with iOS app badge numbers where I cannot set the badge to zero unless I set it to something else first...
- App received a notification through APN which includes setting the badge to, say 1
- Open the app which does a specific reset of the badge to 0 (has no effect)

I have to restart the App completely or set it to non-zero followed by zero again to get the badge to clear.

Looks like some internal storage in the iOS Tabris client that does not retrieve the current badge value on startup, so it thinks it is already zero, thus setting to zero will have no effect, so it doesn't bother doing the set to zero... but in fact the badge wasn't zero because it was updated via APN!

Hope that makes sense... guessing just a simple initialisation thing inside the Tabris iOS client?

J