Joycon rail doesn't work after replacement

After buying a new replacement right joy-con rail on iFixit (along with other components that were successfully replaced) this is the only component that still does not work. There is continuity along various pins on the new rail, but the Switch does not recognize any joy-con is attached (I’ve tried multiple known working ones). I’m positive the repair itself went well.

After thoroughly cleaning the FFC connector and ensuring contact with the rail’s FFC, is there any other part aside from the rail and it’s cable that could be causing this behavior??