According to the Hat, those three poses of Obi-Wan’s are very deliberate.Â
The first pose, which we saw in RotS and TCW, is demonstrating that Maul threatening Luke triggers Obi into responding like he would as a general, which was never an occupation a Jedi should have taken. So there’s something inherently unbalanced about Obi-Wan taking that pose, which gives Maul an advantage.
But then he gets a moment to reconsider and remember he’s not that same Jedi any more, so he switches to the pose we see in ANH. He’s grown. He’s no longer that same Padawan who was traumatized by his Master’s death (which, fun fact: James Arnold Taylor deliberately played his Obi voice younger in TCW when Maul showed up to hint that Obi is reacting from that same place of hurt and uncertainty when Qui-Gon died). He’s a Jedi Master, one no longer tied to the dark shadow of the Clone Wars.
Then he switches to Qui-Gon’s pose, both as a way to honor his old Master but also as a way to play the same trick back on Maul. Trigger a specific reaction from his foe, and idk if you noticed or if someone already pointed it out to you, but Maul tries to get Obi with the same move that killed Qui-Gon. Hilt to the face. But Obi-Wan knew it was coming, ducked, and used the opening to strike his fatal blow.
The level of detail that was put into this episode is absolutely astounding.