Some files consistently fail when converting multiple documents.

What I do is just send the same 12 files (again and again, as I'm trying some things out) in 12 consecutive api calls to the editoria typescript recipe.

So what's interesting is that I noticed the same three files failed every time (with an empty response error).
Even more interesting is that I tried one of the files on its own and it worked just fine. From then on, it doesn't fail in the batch api calls either.

I'm using ink through the pubsweet components btw.