Firefox and Cliqz tabs crashing at GOV.UK government pages

On 08/04/2020 20:23, Graham Perrin wrote:

 > Firefox 75.0_1,1 tabs crashing or mis-rendering at some www.gov.uk pages
 >
 > Most noticeable today at <https://www.gov.uk/coronavirus>. 
Screenshots available on request.
 >
 > AFAICT the same types of problem with 75.0_1,1 on both r357746 and 
r359628.

The problem persists with r359750, is reproducible with a different user 
account, is reproducible with Cliqz browser. As far as I can tell, only 
bugging UK.GOV government pages.

Occasionally a page will appear OK (e.g. the screen to the left at 
<https://i.imgur.com/ROO9FIN.png>), more often the page will appear 
wrong (screen to the right, safe mode).

Most often: the tab will crash before the screen can be read. Crashes 
seem to occur at load time, towards the tail end of content loading or 
rendering.

More shots of what appears to be mis-rendering, Firefox with a refreshed 
profile in safe mode:

<https://i.imgur.com/rNp20f5.png>
<https://i.imgur.com/TuqYnAe.png>

I have .core files from both Firefox and Cliqz, should I report a bug?

(Also I'd like to take this opportunity to learn how to interpret parts 
of a .core file, I'll do what I can with man pages but might need to 
seek help in IRC.)

----

grahamperrin_at_momh167-gjp4-8570p:~ % date ; uname -v
Sat 11 Apr 2020 01:09:15 BST
FreeBSD 13.0-CURRENT #52 r359750: Fri Apr 10 03:33:09 BST 2020 
root_at_momh167-gjp4-8570p:/usr/obj/usr/src/amd64.amd64/sys/GENERIC-NODEBUG
grahamperrin_at_momh167-gjp4-8570p:~ % pkg query '%o %v %R' cliqz firefox
www/cliqz 1.34.0_1 FreeBSD
www/firefox 75.0_1,1 FreeBSD
grahamperrin_at_momh167-gjp4-8570p:~ %