just because this is a fixed resistance machine, that does not mean it is safe however you performed it. knee injuries are a big problem when it comes to training and a lot of the time it is not because of squats or leg presses, but leg extensions and leg curls.
in a lot of people, the quadriceps muscle group(Vastus Lateralis, Vastus Medialis, Vastus Intermedius, Rectus femoris) is more dominant and powerful in one side rather than the other, which might not seem important at first but when you consider the fact that muscles affect each other and physical structure in general, it seems reasonable that this can affect health so based on that, I like to train unilaterally(one side or one leg at a time) to understand whether there are any imbalances.
also, I tell you a small cue if you have any knee problems. make sure you leave your comments and likes if you liked it and share.