@JacobGP I took the content you provided and ran a gatsby build in our gatsby example repo and, unfortunately, was unable to reproduce the error you are running into. I also do not see any obvious issues with the content json.
I am wondering if there is some code in one of the custom components that is the source of the problem. Can you try removing blocks from the content until the error goes away, then add them back until it shows up again to maybe be able to narrow the issue down to a particular component? It might be due to a particular value of an input on a component as well.
Another idea: do you happen to be lazy loading any registered components? Sometimes bundlers can have an impact so I am wondering if that might be the issue.