It would be an awful mistake on his part if he introduces a brand new ability & fails to draw it correctly in multiple panels.
He could easily have forgotten to go back and draw the tomoe before submitting the chapter to Shonen jump. It can't be just a normal rinnegan. That would be dumb and plus it would be in both eyes if it were a regular Rinnegan.
OT as far as we know, the Rinnegan doesn't have the same properties as the MS, so your argument is flawed.
What has been stated is that the Rinnegan is Hagoromo's Dojutsu and his alone. He said that Madara only got the Rinnegan because he had the Sage's Chakra. Also, Viz translated Sasuke's eye as the "One-Eyed Rinnegan" so it appears to be a separate Dojutsu.