Is there any heating issue with Ringing Bells Freedom 251 ?

The smartphone is yet to be available. In fact, there are no sources to indicate that the production of the unit has commenced. The review units provided at the time of launch happen to be from a competitor - AdCom. Without even a prototype in hand it would not be possible to assess the possibility of Hest issues or any other such problem with the Freedom251.
However, given the fact that the device is being made available at such a low price, it could be possible that it uses some low cost components. The processor make has not been revealed so far. Using some substandard processor can result in heating issues in the phone. Having said that, I would still consider it to be too early to predict anything related to performance.

Fun part about Freedom 251 which makes it look like a scam is non-production. There are not even single units of Freedom 251 because for promotion company used a model of smartphone with same specification from Adcom. As per Ringing Bells, soon they will start manufacturing the devices and will be delivered by June, 2016.
With no units for testing, experts can't say a single word about the device. Looking at the smartphone price and specifications, it is definite that it will come with low-quality hardware components . It may or may not cause heating issue but results are still yet to be revealed.