Have you looked at anything upstream/downstream of the knee?
It could be tied to something with your hip mobility.
It could be tied to something within your ankle mobility.
You are seeing it at your knee, but that may not be where the actual cause it.
It may present at your knee based on something you are doing at another place within the system to create slack within the system so you can get into the desired position/shape.
Having the pain in the same pain in the same spot on both sides illustrates you are doing the same thing on both sides.