Trouble building from cloned image

[gitonthescene]

Hello there. This looked like a neat tool which I was hoping to use. I spotted a problem with the demo site if you click on My First post and then click on "Here", you're taken to a dead link.

I thought I'd try to fix it, but it looks like the learning curve pretty steep. I may be missing steps, but documentation is pretty thin.

I cloned the repository and ran "yarn install && yarn run build" and ran into errors. These errors seem to be fixed by upgrading outdated packages. Should the yarn.lock file be updated in the repository?

After updating I tried to run gatsby serve, which serves up the first page just fine, but the routing for the react-router doesn't seem to work as all the links are dead links. Is this an issue with gatsby itself?

I do a bit better if I run "yarn run develop", but if I descend to the "Here" link and go back and forth between the links the server seems to go unresponsive. Again, this may be an issue with gatsby itself.

I'm mostly writing to find out if you've run into similar issues and how you handled them. I'd love to pitch in, but am trying to avoid chasing my tail too much.

Thanks,
-Doug

[gitonthescene]

FWIW, for the last error, I noticed the following in the console:

"The connection to http://localhost:8000/__webpack_hmr was interrupted while the page was loading."

This appears to be a Firefox only issue

P.S. There's another non fatal error even in Chrome.