Confusing computer analysis

I have just started trying to analyse my games with a few passes, first on my own, then with varying levels of computer assistance. I am a little stumped by the computer analysis in this game however. The position was as follows:

My move which I identified as bad was 6. Nf3??, which clearly kicks the black Knight and begs the response of 6. .. Nxb5 almost forcing black to take a free Bishop.

I figured I should have moved my Bishop on b5 somewhere out of the way of the Knight on d4.

According to the chess.com analysis, the best move was 6. Be2. When I tried it out in the analysis, it is marked as an inaccuracy, the best move would be 6. Bd3.

I tried out the suggestion and the analysis marked 6.Bd3?! as an inaccuracy. the best move is 6. Be2.

Usually when I see a rating difference of +1 in two moves, both positions agree which move is better even if not by exactly the same amount. In this case, in each position, the other move is being evaluated a +1 more than the one being looked at. Is this normal? What does it mean?