The scanned image from the instructions came from the Hobby Search website. See the part in the diagram labeled E22? When you assemble the frame for the right leg, you are supposed to slide the E22 cover over the joints.
I lined it up and slid the piece down and it got stuck before it reached final position. I did not want to scrap the leg (or the model) so I ended up soaping up the leg and pulling the part off careful with my hands pulling the part and a plier holding the joint piece.
Once that was off and I dried the leg and used a file to trim down the inside part the the cover slides down over. The cover still is a snug fit but does move up and down as needed.
I’ll do the left leg tomorrow. This model is well thought out but not having any polycaps has introduced some interesting changes to the normal design. The plastic pieces that form the joints are slightly softer that say the white plastic outer pieces. Theses joints work well for a model: you pose the model, admire it, and leave it alone. “Playing” with the model would just mean broken parts.