Let's say someone who was able, and able to keep it quiet, was ordering the production of large amounts of new explosives... would that make a noticeable dent in the raw nitrates markets?
There is nothing mysterious going on here, natural gas ramped down and is ramping up too late to meet the demand and as it is challenging to store it is very vulnerable to production/consumption mismatches.
If what you suggest were happening, it would not be noticeable one way or the other given the effects of the above.