It has been ongoing for me for almost two weeks. At first I thought it could be my phone, but I got a new phone last week and it has been happening in the new one too. One crashes was system wide and caused the phone to reboot.
I suspected it could be a custom extension that I use (Control Panel for Twitter) but happens even while the extension is disabled.
Same here, started about the same time. Sadly the crashes aren’t catched and logged…other crashes appear under settings > about Firefox> crashes.
It’s not even site related - after restarting firefox the sites load as expected.