My T5's rear view mirror is/was floppy. When set to a position that suited me, the next bump in the road would cause the mirror to flop into an unusable position. The mirror hosts the display for the Reversing Camera and is relatively heavy. Positioning the mirror just off what is optimal for me is quite stable suggesting it is just one position that is a bit loose in the swivel mechanism.

My fix was to undo the 4 screws that hold the swivel mechanism on the back of the mirror assembly and rotate it 180 degrees. A road test has convinced me the problem is fixed.

Might be useful info for someone else.