The issue wasn’t whether Flynn would overturn the sanctions. It was whether he’d discussed the sanctions. He said straight up that he had not. But he had; it was a lie.
My point is that he said nothing wrong. He just asked Russia to hold off on retaliating against the U.S., and the most they could say is that he gave the “impression” that the sanctions would be overturned (they weren’t), but he said the sanctions could be discussed in the future. There was nothing that he said wrong there, and I can see how he felt he didn’t discuss the sanctions as he never promised anything regarding the sanctions.
We know that Trump was aware of this for a few weeks prior to Pence finding out. Trump didn’t get rid of Flynn at the time nor tell Pence because I don’t think Trump thought it was a big deal. Then it hit the media, and the optics were bad because they tried to use the Logan Act (ludicrous) and call him a liar because the media made it look like he told this big lie to Mike Pence. Trump let him go, but he shouldn’t have because now they are using the exact same playbook to try to get Sessions.