I have had one of my projects get hidden but never gotten a notification/email about it. 

I don't know what makes them send an email. I hope you get an answer!

It might be that they did not receive it and if you stuck with this problem you can report a problem if needed if still not helpful we can figure what is wrong

Hi Coder Guy ✝ #makegamanite,

Our moderation team is generally instructed to send messages when hiding projects, but this doesn't always happen. If a project very clearly violates our Project Guidelines, then a notification may not be sent.

If you'd like more information about specific projects, please submit a hidden project appeal: https://docs.google.com/forms/d/e/1FAIpQLSe8sOJPtzuYKxO12juR-G_7hFJXW-Jkt_zLD3JxMg3FuGvX5w/viewform

I hope this helps!