While looking at a suggested edit on a site I'm not logged into, I noticed that anonymous users can't select the side-by-side Markdown diff option on that page because
full-anon.js doesn't contain the definition for
StackExchange.suggestedEdits that the page (unsuccessfully) tries to call
This is fairly minor since you can get basically the same view by looking at the post's revision history, which you'd have to pass through on your way to the suggested edit anyway if you were navigating by the relevant links. However, it would be nice if the suggested edit page worked like it's supposed to in this case, or if not that, at least didn't produce an error.
Also, while I'm nitpicking, I should point out that the icons for the Markdown diff in the revisions and suggested edits view are different as seen in the following screenshot and artist's rendition: