Same here. Never allowed Android touch my Jolla. Still, 2% battery drop per hour is normal with no applications running, WiFi on and connected. With WiFi on and not connected this can increase four times.

The smallest overnight drop I have ever seen was 8%, and that was when I went to bed particularly late (long after midnight) and woke up as usual (about 05.30).

This is all on Jolla. But if others are reporting similar on their Xperias, then it is likely not a hardware issue.