Basic information

Steps to Reproduce:

1. Enable strict tracking protection
2. Navigate to any listing from https://swappa.com/mobile/buy/lg-v40-thinq/att

Expected Results:

Page loads quickly, as it does in standard protection mode.

Actual Results:

Page "finishes loading" (throbber disappears) but page content appears after 2-3 seconds. This is very annoying when browsing this site.

More information

Screenshot: (if relevant, please attach a screenshot or screencast to this bug report)

Profile URL: https://share.firefox.dev/2M8vdiX

Basic systems configuration:

OS version: Ubuntu Groovy

GPU model: Intel Graphics 630

Number of cores: 4

Amount of memory (RAM): 24GB

Thanks so much for your help.

This also happens on desktop Firefox with the responsive design mode, but only if Strict mode is on (not in a private tab).

It's asynchide:

	<!-- Google Optimize -->
	<style>.async-hide { opacity: 0 !important} </style>
	<script>(function(a,s,y,n,c,h,i,d,e){s.className+=' '+y;h.start=1*new Date;
	h.end=i=function(){s.className=s.className.replace(RegExp(' ?'+y),'')};
	(a[n]=a[n]||[]).hide=h;setTimeout(function(){i();h.end=null},c);h.timeout=c;
	})(window,document.documentElement,'async-hide','dataLayer',4000,
	{'GTM-N23SSBG':true});</script>

The related shim I'm working on in bug 1637329 seems to do the trick here.

This is now fixed by SmartBlock as of bug 1687942.