Modpack version
Latest Version

Issue
a SAG mill can turn 1 coal piece into 2 dust, and 1 sulfur (it's by chance, but regardless it's possible). You can then turn the coal dust into a coal piece with a multitude of machines, and repeat the process, giving you free coal and sulfur.

Thank you for the report, I will investigate the issue.

Follow up on this, I found a similar issue, but this time with quartz.
quartz in SAG mill-->1 quartz dust, 10% chance for another
quartz dust in enrich chamber--> quartz