I keep a pause-lock on my smelters, weapon-smiths and exotic sawmills because i buff them when i have the materials for the things to work, lately ive noticed that when the resources become available again after depleting my stores, smelters and weapon smiths are resuming without my prior authorization.
the blue zzz's dissapear and the building resumes its active animation, however the info panel still states the the structure is paused.

while its only a small annoyance, i dont catch it all the time - and in a trade system where everyone seems to be out to screw everyone else, getting hold of those materials isnt cheap.