Training dummy frequently overrides higher priority jobs

My crafter has priority three crafting job, even after manually assigning them and having them start, they break off and go and train melee. I've noticed the same with other important jobs like farming and gathering. It's -2 degrees and snowing and my builder needs some trousers!

Expected: if guarding controls the training activity, then they respect the priority of that assignment, and only go and do it every now and then.

Or alternatively, combat training is a separate activity with its own priority and/or it only happens when they're enlisted and not in combat.