okay so I am trying to make a walk cycle and have the first 13 frames set up with the following sequence Contact > down > passing > up > Contact and I would like to mirror and flip this animation to complete the loop. However when I paste the flipped pose it only pastes the spine or any single bone that doesn't have a left/right equivalent of itself.
Flipping each bone individually doesn't work either and messes up the animation. I checked every bone and each of them have been marked correctly with a left and right tag with all of them correctly parented to the right bones. I'm not sure how to fix this. Please help, I could do it manually but i would prefer to find out how to fix it since i have to do this again for a run/sprint animation as well and it would make things go much smoother.
Not sure if answering my own question is allowed but maybe this will help someone figure out what's wrong with their rig if they come accross this issue.
So it turns out that for my specific case I had the arm and leg bones directly connected to the spine by another bone (clavicle and hip bones) which somehow messed with the ability to flip a set of keyframes. So I remade the armature from scratch with the same bones and had the arm and leg bones separate but still parented to the spine and it all flipped perfectly fine. I found a lack of memory also prevented a certain amount of keyframes from being flipped, so the less bones to animate the smaller the chance you'll get this bug.