@DaiJooky I'll try to recreate this in Arcade Splitscreen, but my assumption is the following:
While a character is standing up from the ground after a knockback effect, he/she can block any incoming attacks or abilities that can be blocked ( https://answers.ea.com/t5/Bug-Reports/Characters-can-shoot-block-on-the-ground-before-they-stand-up/m-p/7018706 ). However, even if you turn your camera around while fallen, your character model won't turn. This leaves me with 2 possibilities: while fallen you may be able to block attacks from any side (unlikely IMO) or as you may rotate your camera while fallen but the character model doesn't follow this movement, the blocking may respect your camera angle instead of the character's model, but when applying the blocking animation the game will respect the orientation of the character model instead of turning it to respect the camera orientation (more likely IMO).
Either way, I'll test this in Arcade Splitscreen this weekend along with the other tests I said I'd do.
Also, while blocking a saber attack from the front (should) always work, and blocking from behind (should) never work, blocking from the sides is tricky, I tested this back in April and it seemed somewhat inconsistent. Maybe depending on the attacking animation, the hit point may differ, and as a character's side is the limit between a blockable and an unblockable area, depending on the attack it may be blocked or not.