It is believed that this was an editing error, and that the clones should have been wearing the gray patterned armor of the 41st. This is actually the only time we see all white Phase 2 clones. Behind Mace and Obi-Wan are a couple of clones wearing all white armor. One interesting note: there is a scene on board a gunship with Yoda, Mace, and Obi-Wan flying in one of the Coruscant sky lanes.
This isn’t explained in the films, but in the US military, it is not uncommon for small detachments to be temporarily assigned to other larger units when it is deemed necessary. Simultaneously, members of the 41st, wearing their grey trim, can be seen fighting alongside the 212th on Utapau. That same unit is seen later on Kashyyyk, although we only see them wearing camouflage patterns on scout and ARF armor configurations. In Revenge of the Sith, they wear the white armor with gray trim (as represented on this figure) in a key scene when they are preparing to leave Coruscant for Kashyyyk.
