Boost App showing poor performance

I have Telus Boost set up at home - using 5 routers as my house is quite large.  Performance is generally good.

A firmware update was done on the boosters a few days ago (Sept 23 2019) - this appeared in the Telus Boost App notifications area.

I have noticed the Boost App is showing "Poor" performance on 3 of the 5 devices (this was not the case before).

I have shut down and restarted all of the routers including the Telus modem but this does not change anything.

Performance is generally good throughout the house but I am wondering if the App is detecting interference.

The house is about 10 years old and the original owner installed a lot of audio cables in the walls.

Does anyone have any tips for troubleshooting this?  I have done speed tests via the Telus Boost App throughout the house and they generally render fairly close to my wired speed (150 Mbps).  But I do see glitches from time to time and I am wondering if I am overlooking something.