It was a documentation/error response bug in their API, so it was hard to reproduce trivially. I gave them some source that reproduced it (https://github.com/sa

It was a documentation/error response bug in their API, so it was hard to reproduce trivially. I gave them some source that reproduced it (https://github.com/samcgardner/neg-lb-initialiser https://github.com/samcgardner/neg-lb-initialiser), which really seems like it ought to be sufficient - it reliably reproduces wrong behaviour.