I feel I've hit an error in npm regularly that said it was a bug in the tool, for it still to end up my mistake. While you may well have gotten the tool into an unsupported state, you were never supposed to get there. That makes these "it's a bug" messages less useful to me.
You still found a bug - the error claimed it was a bug, but it wasn't!
The point of technical error messages, imo, is to tell the developer what they did wrong to get into this state. They can't be allowed to be wrong, otherwise developers stop trusting them (this bites us a lot - we get dozens of incidents along the line of "error says very specific thing related to my scenario is configured wrong - is it actually?")
