Okay so in the first version of Marshmallow it was possible to move apps to the SD card without having to set it up as internal storage. Now they removed this feature, only allowing to move apps when you are using the SD card as internal storage. Does anyone if it is possible to downgrade to that first version of Marshmallow where it was possible to do this?
It is possible by using TWRP or any other custom recovery of your choice but you must have desired firmware file as recovery flashable zip archive first. Unmounting adoptable storage and performing all available wipes from recovery before downgrading is also required. You can find detailed instructions on what custom recovery is and how to install it on specialized forums (I recommend XDA Developers one) as well, as desired firmware version for your downgrade (head to your device thread and seek there if you interested).