Is there any heat issue with Micromax Unite 3?

As far as the reviews come up from reputed review sites, the Unite 3 has no abnormal heating issues. There are instances of increased temperature at times, but that is common with most phones.
In short, the phone has no heating issues that is beyond explanation.

There are normal heating issues. If you will go for a Xolo phone then almost each and every xolo phone heats up, same is with unite 3. It heas up a little while playing games.