I have this exact same problem, in fact I could have written your comment word-for-word. I also cannot reproduce it reliably, but it started in August.
I also switched from Chrome, but for slightly different reasons...I got to thinking about Google, and Chrome,and ad-blocking, and it occurred to me that Chrome will probably never allow extensions on Android, not because it's technically not possible, but because ad-blocking is bad for business (if your business is showing ads).
How does the Chrome team reconcile this? We know that ads are annoying, and ads can track you, and some ads can even be malicious. It seems that blocking ads make a browser better. But the Chrome team is not allowed to block ads on Android, so they are purposefully making a worse mobile browser.
Anyway, I do a lot of surfing at night in bed on my Android tablet, and I'm going to stick with Firefox.