She was in ROTS played by the same actress wearing different clothes.
The prequel trilogy is stupid.
Again, I suppose there’s some “logical” explanation why Mon Mothma does not appear at the Death Star attack run briefing, does not appear as the attack on the Death Star is unfolding, does not appear at the medal ceremony, does not appear anywhere on Hoth…
But now, hey! She’s hanging out in a leadership role in the Rebel alliance in a movie scene that predates the 1977 movie.
Disney did not waste any money on continuity experts.
Obi Wan wore the same clothes for six movies (even when he was meant to be on the run under a slightly assumed name).
The prequel trilogy is stupid.