Snapping / popping knee when hyperextending after felling mild pain on pes anserinus

Hey guys,

Over the last 3 months I've been feeling 1/2 times per week mostly practising sports (10-30 degrees of flexion reproduce the issue when my foot is on the ground) or sitting on my heels a mild pain on the pes anserinus region of my right knee. Once in this situation, to make the pain go away, I hyperextend my knee, having a snapping / popping feeling. I've had ACL reconstruction on my both knees. I'm also very flexible: I can hyperextend my knees and the biceps femoris tendon snap over the fibula's head on my both knees.
I've listened to a few doctors and physical therapists but I still don't know exactly which kind of issue I have.
Have you heard of something similar to this or could you recommend some actions to help solving this issue?

Thanks,
Vinicius Artur