I have a GameSir T1 controller paired with an Android 7.0 tablet running the current version of QGroundControl from the Play Store.
On the Joystick calibration page, the Roll, Pitch, and Throttle controls all work as expected. The roll and pitch are at the center when the right stick is centered, the throttle is at the bottom while the left stick is centered, and these controls all move in sync with the Axis Monitor.
The yaw control is a different story. When the left stick is centered, the yaw is either all the way over to the right (usually) or all the way over to the left (sometimes). It doesn't respond very well to the left-right motion of the left stick. The Axis Monitor correctly reflects the motion of the stick.
This is in mode 2. In other modes, whichever control is mapped to the left-right motion of the left stick has this behavior.
Here is a video if it's not clear what I'm trying to say.