[Bug-gnuzilla] [Icecat 60.3.0] Some favicons appear as white squares

[somebody]

Hello,

I am noticing an issue with Icecat 60.3.0 where certain websites will 
have the favicon on the tab show as a white square rather than the 
expected icon. I have attached a screenshot of one URL that consistently 
does this for me: https://riot.im/app . This is also happening for me 
when logged into Discord. I've tried this on Icecat for Windows and 
GNU/Linux using a fresh profile with default settings. I'm seeing this 
occur on pre-compiled copies as well as a copy I compiled myself on 
Parabola GNU.

Any suggestions on how this can be corrected would be appreciated. 
Thanks!

2018-12-07 10_53_53-Riot - GNU IceCat.jpg
Description: JPEG image