Sometimes after changing content in contentful you may get a TypeError: Cannot read property 'internal' of undefined
error. The only fix I've found for this is to unpublish all contentful component pages, and republish them ~4 at a time, building each time. Relevant issue here:
contentful/rich-text#53
gatsbyjs/gatsby#6949
Embedded entries don't resolve when using gatsby develop
: contentful/rich-text#46
gatsbyjs/gatsby#10592
gatsbyjs/gatsby#9821