I am not sure if this is the right place to report this, but here it goes.
After the recent Gmail update the inbox will not load when you start Firefox. It will just return a blank page.
It requires a refresh before the page loads.
Here is the URL:
I imagine that many users will have gmail pinned, so I think it is worth a fix. Other pages might not load too.
To reproduce: Pin your gmail inbox page and reload Firefox. Gmail will return a blank page after a while.