when a MOB that does not light on fire around him

This ticket is very difficult to comprehend, please use the Bug Report Guidelines Here when posting issues.

You mean that a burning mob does not emit light ?
Or that a burning mob does not light other mobs / blocks ?

Please do not mark unreleased versions as affected. You do not have access to this yet.

Duplicate of MC-2521.

Your sentence needs to be finished. Are you choking or something?