Varying calculation depth
what the heck chess engine

Varying calculation depth
Same depth, it was 18. It wasn't on self analysis, and wasn't on unlimited depth.

I was practicing the Italian game and this happened
this was me responding to Bd3 then going back and playing the "best move", why did this happen
That's not at all uncommon in some positions. I've had that happen on standalone engines where I went through a move to show that it wasn't good, went back and went the new move that was good to find out it wasn't, and repeat.
I believe I was letting it think to a depth of around 30 at the time.
I was practicing the Italian game and this happened