The docs listed G1 as A,B,5V,GND and G2 as GND,5V,B,A, the same fact read from the bottom with no frame stated. In reality G1's terminal order is mirrored on G2/G3, so a harness moved terminal-for-terminal puts the encoder's supply on MCU pins, and G2/G3 also swap A and B at the MCU. They now give every header in one shared frame next to the firmware motor number. Classic board revision, harness and firmware drift with no single source.