I have exactly the same problem, but on my Windows client. Also using Shaw Cable (Vancouver). Whenever I open the desktop windows client my internet just dies (not even the client works). Started happening sometime last week. Tried reinstalling the app multiple times to no avail.
The web version works, but it stutters more than I can stand.
So the answer turns out to be that the Cisco DCP 3825 is the problem.
I had a small portable WiFi router and bridged that to my Cisco DCP 3825 for internet. Then I connect my iOS devices to the router and ran Spotify. No connection drop and internet still worked on all devices. Then tried it with a another router I had around connect directly through ethernet and same, it works.
In conclusion, if you have Shaw internet and have the Cisco DCP 3825 modem/router get another router or complain to Shaw to see if they can upgrade your modem.
The issue is specifically with this particular Cisco modem/router. It could the the Shaw firmware. Haven't had any problems with any other routers or modems. Highly unlikely that Spotify will try to patch their app to a problem they can't test.
In any case, this Cisco modem/router is a few years old now and the performance of this Cisco modem/router not that good to begin with. Needed to restart it ever couple days as the wifi connection would drop.
Sad to say but I have the same problem too on my Macbook Pro. This is unfortunately terrible. On my Android phone works without problem for now. When I open Spotify kills the wifi connection for all other devices on the network E.g Chrome, Safari. When I want to connect my wifi, first I must close Spotify app and then either I have to put the Macbook to sleep mode or restart the computer.