There is one thing that really bothers me. I tried Opera mini Beta, but now I have the same issue.
I open multiple tabs and after I check the first one and switch to the second one, even only after two minutes, it is refreshing the page. It's very annoying. It's the same when I have some tabs opened and switch to Opera mini later. They all refresh so I have to wait a lot. There is no way to avoid it!
I have been using Opera mini for many years and there was not this issue before. But I don't remember when it started. Maybe half a year ago.
I'm using Android 5.1.1