Hi @gariepyt,
That’s an unfortunate issue which is my fault, but hopefully we will get it fixed soon. For now, try this:
sudo snap install core && sudo snap refresh core
That’s all you should need to do to fix it. Having an up-to-date snapd package from apt would also fix it for Ubuntu 16.04.
By the way, if anybody else runs into this in the next week or so, and you haven’t run the above command yet, it’d be great if you could also post what your OS is and the output of snap version.