Push messages longer than 255 characters not reaching iPhone

I'm trying to send a push notification to a device - which is longer than 255 characters.

I'm not getting any errors from Apple servers but the push notification does not reach my device.

1. Using Pusher (http://ift.tt/M5cofk) the push notification DOES reach the device - using the same certificate.
2. Sending a push notification smaller than 255 characters DOES reach the device

What could be the issue?

via Chebli Mohamed