Pocket 'View List' stopped working in Firefox
I've been using pocket daily for a long time, and just recently the 'View List' feature (i.e. view the pocket website page with my saved links) stopped working in Firefox. That is accessed in the normal way using the Pocket icon in the address bar, or with the link: https://app.getpocket.com/ - they both go to the same address.
When that Pocket 'View List' page is accessed, it gives all indications of having loaded fine, but all that shows is a completely blank white page with the horizontal line and faintly greyer section at the top of the page, and absolutely nothing else.
Firefox version: 78.6.1esr
I'm pretty sure this was broken on a recent update (of Firefox). I'm also pretty sure many other things were broken in Firefox by recent updates - never had Firefox so damaged by an update before - things like on Amazon website pages (to pick something well known), product images randomly don't load (refreshing gets them to load), pages randomly display garbage (refreshing brings them back), etc, pages load fast but elements on page are not active (can't be clicked) for several seconds on complicated pages like an Amazon product page - never had this happen before recent Firefox update - I don't know if this is all related, but it feels like it is (and that Firefox has been broken in many ways only recently).
All these things, including viewing the pocket list, still work fine in Chrome.
Anyone have the post issue in Firefox? Or the other issues just recently? Is there a fix for this?