Docked Switch Overheating and Glitching Problem

Hi my switch has a over heating problem but only when it's docked. I can't seem to find a reason as to why it only over heats while it is docked. After about 2 hours of gameplay the switch begins to freeze and/or glitch. Any recommendations or words of advice?

I ended up just sending it to Nintendo and getting repaired under the systems one year warranty ,because the system began to lag and later freeze. But putting it on its side did work for a while but did not completely slove the issue. Ether way thank you for the response.