Steps to replicate the issue:

1. (Assuming you are an admin on cswiki.) Visit https://cs.wikipedia.org/w/index.php?title=Jak_se_chov%C3%A1_antilopa&diff=24332159&uselang=en. The title matches the now-deleted page to which the revision belongs.
2. Observe "One revision of this difference (0) was not found."

Next:

1. Visit https://cs.wikipedia.org/w/index.php?title=ABC&diff=24332159&uselang=en. This URL refers to the same revision ID, but changes the title to garbage.

Now the correct revision ID is displayed (with a link), even though a "slightly invalid" URL was used.

You can even omit the title completely: https://cs.wikipedia.org/w/index.php?diff=24332159&uselang=en. The page then assumes the "default" Main page title (T380102).

What should have happened instead?

The revision ID should always be displayed, and if you have sufficient rights, you should get a link to view the deleted content.

The UX could also be improved:

• Some elements (e.g., Help link) are useless or have different/conditional appearance even though it's basically the same page.
• The link should have diff=prev, so that a diff is shown directly.