I am a bit confused. I have a power module (Fishbonne) that was provided to me by Emlid together with a Navio+. I never used it before, but today I started to build another rover with a Navio2. I took a standard 1 to 1, 6pin power module cable from a pixhawk and was surprised to see, that the polarity is actually reversed. Initially I thought, I had done something wrong, but every other power module (sadly, they are all broken somehow) I have, has the right polarity with a 1 to 1 cable.
Luckily I noticed this, before actually powering the Navio2 with it. I never read a note about this anywhere in the docs or on the forum.
I have the answer for your confusion
FIshbonne uses Molex connector and its onboard port has the alignment pins on the bottom, while DF13 port has them on top of the port. That’s how a straight cable gets reversed - by plugging the connector upside down on the Fishbonne PM power port (red wire ends up on the right when you look at the connector from front and top).