Downlinks not working correctly

[beavis88]

I'm trying to send (via MQTT) downlinks with payload size bigger than maximum payload size of current device data rate conditions.
I expecting to recieve lost events or something but nothing happens! Downlink just not delivered silently. How to get full feedback about downlink delivery result?

Moreover, i looked into server events and there are a lot of downling_missing events. But how it possible if downlink payload size are exceeded packet limit? This packets can't be sent to the end device.