When processing the batch of schedule files, the JavaScript engine would stop doing any work half-way through, without any error message I could see or exception I could catch. The JSEngine object was created with an initial memory allocation of 100,000. Upping this to 1,000,000 "solves" the problem for this particular batch, but it's hardly a fix; presumably a larger and more complicated batch would at some point cause the same problem. Nothing in the docs helps pinpoint this, or suggests any way to catch this situation and report on it. I'm still working on this.