Considering the movie went out of its way to explain how its version of time travel worked, it did a pretty good job of sticking to its established rules. Past Captain America thought he was fighting Loki, Thor talking with his mother who obviously doesn't reveal their conversation, and Tony snapping Thanos and his army back to their own timelines without any recollection of what happened. Those all seem to hold up for me. We just have to assume that Steve was able to live secrety in the past without anybody discovering his identity who made it public knowledge. Anything missing?