/rest/api/1.0/render broken?

I know that /rest/api/1.0/render has been long deprecated but it has been a good friend of us app developers, especially when rendering user wiki markup text based on an issue.

Is it possible that /rest/api/1.0/render is finally broken? It doesn’t display images as it used to…

The body:

"unrenderedMarkup": "Some !image.png! *body*"

The response:

<p>Some <span class="error">No usable issue stored in the context, unable to resolve filename &#39;image.png&#39;</span>