"Connect to a Device" inconsistent

[sbeckymart]

Premium user (USA) 

four Mac devices that I play Spotify from (older iPhone, 2016 Mac Air, 2019 Mac Pro, latest gen iPad).

They all connect fine to my speakers--my question concerns seeing the various Mac devices on "Connect to a Device."

I checked that they are all on the same wifi and all logged in to Spotify. Yet I rarely see all the devices under "Connect to a Device" and can't figure out why. For example, my laptop was just showing the laptop and my iPhone, and I was playing from the phone. The playlist ended and when I went to start another, the iPhone disappeared from the laptop "Connect to a Device" list--but I could see both on my iPhone, and once I started playing through the iPhone, it showed back up on the laptop list. Am I doing something wrong?

Plan

Free/Premium

Country

Device

(iPhone 8, Samsung Galaxy 9, Macbook Pro late 2016)

Operating System

(iOS 10, Android Oreo, Windows 10,etc.)

My Question or Issue