hey ehwright that is odd!!
I have seen it before, a long time ago. But I completely forget what the reason was.
Could you try with the OpenAPI definition loaded into https://editor.swagger.io and see if the issue exists there?
If it doesn't, you may need to update to the latest version of SwaggerUI.
If it is visible there, then could you please share the OpenAPI definition that can reproduce the issue? It'll help us identify what is occuring.
PS:
To see what version of SwaggerUI you are using, you can go into the DevTools/Console of your browser and inspect the window.versions variable.