When you got a delivery where the STM modules are already populated with headers like in the 1. picture, you still need to connect the 4 extra pins in order to get the STM flashed correctly. With the attached header (see arrow), that does not work.
So you either add 4 wires then need to be soldered on the pcb first and connect them to the header or you add an additional 4 pin header on the lower side of the STM module that then connects to the 4 holes on the main pcb.
Please also check out https://tiltaudio.com/2022/05/05/board-rev-3-10/