MIDI Not working for second deck

Hello, I just bought a pair of Denon S3700. They have motorized platters plus a hybrid midi mode. I have them connected to my DDJ-RR with DVS which is working perfectly. The midi part is giving me problems though.

So to start, I have both decks connected trough USB directly to my laptop. Once I go  to the midi screen in Rekordbox 1 of them does show up and is also midi mappable (some questions about this later, like the browse mapping does not work as it should) the second one is not mappable. It also depends on which of the 2 I connect first. So if I turn on deck 1 first, that one will be available for midi in Rekordbox. If I turn on deck 2 first, that one will be available for midi.

I tried giving them different midi channels. I tried giving them the same midi channel. It does not matter, Rekordbox is only giving me one to play with.

I also checked out the midi data via MIDI-OX. There I can see both decks connected and both send out midi data.

So my question is, what am I missing and what can i do.