No, that is absolutely not a problem. If an interviewer is interested in your OSS contributions, hes's not going to be any less impressed because it's a project he's never heard of.
The simple fact that you have OSS on your resume makes you stand out. Period. I have seen exactly one resume with OSS on it in all the years I conducted interviews.
That's actually quite encouraging, so thank you. I've been trying to find a balance between working on OSS contributions + getting better at "CS fundamentals" (I'm a self-taught programmer, so a bit lacking on the algs/data structures side of things). Which is definitely a disadvantage during an interview, and part of the reason I'm hoping to emphasize my OSS contributions more.