Welcome to the forum @tlingren 
The relations UI is not performing well with very long documents. It is a known limitation that we still need to work through.
If your documents are very long ( 7K characters is probably the limit), then you might want to look for sensible ways of splitting your documents in the snippets. Some users also worked around it successfully using a sliding window over the long documents.
However of your documents are not particularly long, could you perhaps share one of the examples that doesn't work for you? It's probably a front-end issue, since unwrapped version is being rendered correctly.