Great mod! I'm planning on using it for an upcoming mothership I'm designing. However, one issue I have run into, however.
I'm a big fan of using fairings to connect larger lower stages to upper stages. For example: 3.75m Fairing -> 2.5m Separator -> 2.5m Engine -> 3.75m Tank, with the fairing attached to the 3.75m tank. Normally this all works out fine normally, but after installing Recoupler, they suddenly wouldn't separate. I confirmed the decoupler was triggered by staging, and the decoupler no longer had the "decouple" option. After removing your mod, I reloaded the vessel and re-launched it and the decoupler separation worked fine.
If I had to guess, I suspect your code is treating the connection between the fairing shell and it's attached part as a regular attachment between parts, so even after the fairing deploys and the decoupler is separated, there's an invisible connection between the deployed fairing and the attached node.