EX6150/AC1200 WiFi range extender

Recently purchased and successfully installed the EX6150 range extender. Brilliant device with regards to eliminating dead spots however I’ve noticed two issues:

1. the unit itself becomes quite warm, not hot to the touch nor any burning type smell but for an electrical device, it does seem warm.

2. when turned off using the device on/off switch there is a pitched sound, similar to a mosquito! Damn annoying sound that stops only when the power point/supply is turned off. 

Having never used a range extender before, I’m unaware whether these issues are normal or not. 

Any advice would be appreciated.