You took this image from a post of someone
speculating about the cable configuration, not someone who had actually confirmed it. I'm not surprised it's incorrect.
https://www.head-fi.org/threads/philips-fidelio-x3.913807/post-15852911
Someone was able to find a 3rd party cable that worked before:
https://www.head-fi.org/threads/philips-fidelio-x3.913807/post-15876847
https://www.amazon.com/NEOMUSICIA-Replacement-upgrade-Crossfade-Headphone/dp/B01J9V298Q
That cable seems to be out of stock, but the way V-Moda wires their dual entry headphones is that you can either use only one side or you can use a split cable like this. So the cable is probably set up like this:
This would also explain why some cables work with one of the connectors only partially inserted, because those cable probably have the right side wired with the tip as the right channel rather than the ring, so the tip makes contact when partially inserted. But again, I'm also speculating. I wouldn't just order something based off this. Someone needs to check the stock cable to confirm. It's definitely possible to get a custom cable for the X3, you just need to use the proper configuration. You could also just send the stock cable to someone who can shorten it.
Obviously Philips should just sell replacement cables themselves, but given the years of frustration from people trying to get replacement pads for the X2 from Philips that seems unlikely.