Possible Explanation

[Kai NB]

A possible explanation for why Sasuke no longer has tomoe on his Rinnegan could be that the tomoes only appear while he is using Sage Chakra? Maybe it ended up being like Sage Mode, where he has to focus on gathering the Senjutsu chakra before it'll appear. It could explain why he could still use his teleportation tech. It was just without sage chakra being used.

So I still think Naruto and Sasuke still have access to their Sage Abilites, but they simply need to gather it beforehand.

I mean, I don't have much evidence to back this up, but it's not too far-fetched

 

[Madara the Solo King]

It could be this or it was a drawing error on Kishi's part.

 

[The Demon Hawk]

The tomoes are deactivated temporarily, that's all. So now it's similar to the single regular Rinnegan, and can use some techs like Ameno, much like Madara could use Limbo with one eye. And the tomoe version is similar to the dual regular Rinnegan, probably to use Six Paths techniques. Sasuke will manifest the tomoes upon requirement. Right now, he just needs the watered down version equivalent to one eye.