I think it’s a workstation fan on a server board. The CPU is rotated on server boards vs workstations. When the fan matches the board it always blows to the back. RAM modules follow the orientation of the CPU. Parallel to the airflow on server boards, perpendicular on workstation boards.
I've seen the sockets on those boards being "90° off" in comparison to normal AM4 / 1150 / 1200 Socket motherboards which lead to those orientations.