I was trying out the validator on my website and I get different results depending on the input method. Using direct input works exactly as expected, but if instead I use a URL, the results are different and some data are missing. I noticed this happens when using RDFa (from memory, I believe microdata was working correctly).

If I 'change' the source on the left pane, then the results are more complete again.

For reference, the site is https://riv.ar. See, for example:

1. https://validator.schema.org/#url=https%3A%2F%2Friv.ar%2Fevents%2F says that no elements are found
2. If you then make a small edit (like adding a space) and validate again, a WebPage element will be found.