I used Opera Mobile on android for about two weeks. Its adblocker worked relatively well. It wasn't as powerful as its competitors, but it blocked 90% of ads, especially the most annoying ones, and that was enough for me.
From one day to the next, the adblock started blocking nothing else. The same websites I was browsing were now full of ads and popups as if the adblock didn't exist. I even thought the adblock was disabled, but it was active and with the option to allow acceptable ads turned off.
The situation got so bad that I had to switch to another browser until the adblocker was fixed. I don't know if anything has been updated regarding the adblock or if the ads themselves have managed to bypass Opera's adblock. Could you investigate this?