Iron melters remaining active

I had 4 iron melters and pressed the stop button on all 4 of them, to make sure they wouldn't actually use any iron while unbuffed. At that moment I had exactly 1 iron ore, obviously not enough for them to do anything.
When I received 100 iron ore from a trade, and checked my storage, I noticed I had only 89 iron ore left; 12 less than expected. I rechecked my iron melters. While all 4 showed 'Status: stopped' when I clicked on them, only 1 of them actually had the Zzz graphic icon on the map.

So it appears buildings do not always stop properly.

EDIT:

The same happened again, but this time I made sure they all had the 'Zzz' icon on them before trading. I received another 100 iron ore from trade. The 'Zzz' icons disappeared despite remaining inactive, 16 iron ore total taken from my storage.

Update on this, the bug seems worse than expected.

After stopping a building the progress bar even continues to move. Easy to reproduce.
- Find a building with lets say 2 minutes left
- Stop the building
- Wait 1 minute
- Start the building
- Now it has only 1 minute left

This is very annoying for people who rely on baskets on their buildings.

Ferro219 this is a known system mechanic.

When u sleep a certain production item, it always keeps on running until it has about 4- 10 seconds left in it production, while it is sleeping.

When u wake up a production, that will give you an instant production, this is helpful for buffers who keep items asleep unbuffed. when the item is buffed, then started up, the first production is instant and doubled.

this is no bug. the fact that some buildings dont stop when clicked could be from different sources:

-lag
-browser
-alt tabbing
- switching to other tabs in the same browser and then returning, the focus is not always as it should be!