When a web browser widget is displayed in 3d using an actor with widget component, the loaded content scales differently on editor and android. You can try to load following HTML to see the outcome:
<!DOCTYPE html>
<html lang="en">
<body>
<img src="upload://zcH1nmUHF1BuBzWSiPobTLe911W.jpeg" alt="Game Image">
</body>
</html>