What is the logic here? Why the wind arrow is like that?
It happens to almost every session.
Wind direction is calculated from GPS movement data, which can produce inaccurate results when the signal is noisy — common in wave sessions with lots of direction changes.
A fix is coming in one of the next three updates. In the meantime, you can correct it manually: open the session editor and adjust the wind direction there. Since this is a wave session, you can also set the wave direction independently.