Compiling Vyper files results in a 'path exists outside base folder' error

Question

I received a truffle compile error while compiling Vyper files

/VyperStorage.vy - path exists outside base folder

I was working with the truffle VyperStorage Example Box. When I execute truffle compile it shows me the error above. I have installed Vyper through pip. The truffle config.js file is used as default so no changes made to that either.