I have also had this problem with several Logitech mice, including the performance MX
I fixed mine by desoldering and replacing the left microswitch with another (stolen from another, broken mouse). This is reasonably straightforward if you're comfortable with soldering, it just requires quite a lot of disassembly to get to the underneath of the logic board.
Alternatively, and much more simply, you can try opening up the microswitch and bending the internal spring back into shape. This is described in detail [https://www.youtube.com/watch?v=82z-OpHdBgE|here] (not my video).
Hope that helps