Purchased 2 unit deco X60 pack from Amazon in Jaunary. I recently noticed that when my phone is connected via 5ghz band of the deco unit (which was the satellite and is 3 feet away), the internet speed drops to almost nothing. Tried resetting everything, made it as main deco, and turned off 2.4ghz wireless in the deco app.

Post that noticed that 5ghz band is not working properly and SSID is not visible (as 2.4 ghz was already turned off and I was around 10 feet away). But the other unit is working perfectly fine (Attached the screenshot of speed test from both the units when connected to 5ghz).

I don't think that there's any issue with the settings but do let me know if anything can be done about it. 

Saw the same thing in another post (https://community.tp-link.com/en/home/forum/topic/234972) and I guess, one unit is faulty.