Im using Windows and Chrome.
Despite of the OS, on client side I was able to load the STL file with no problems, the errors have come when putting the Vue framework and trying to load the STL file from server side. I know that the file has no problems at all as I have been able to load it, but the problem is that changing to Vue it stopped working, and is not that Vue and Three are incompatible, because the Scene, Renderer, Lights, etc. are being loaded in a proper way.
Creating a Vue instance, putting the code needed to load the STL file and running npm run dev to start the server, and the STL file does not load, STLLoader.js stops at face 20, vertice 2 with the error I put before.