To address this yet again
1) Every single tin is vacuum sealed in the factory. Each tin is placed in the vacuum sealer by hand, it is vacuum sealed.
2) Just because the tin lid comes off relatively easily does not mean it was not vacuum sealed. In the past we had complaints that tin lids were too difficult to get off. You should not need to spend ages trying to get a lid off with a coin! A tin does not need to "pop" when opened to mean that the there was a vacuum seal. You should not need to really yank on a tin lid to prove it had a vacuum seal. Lids can still come off relatively easily and the tin was still vacuum sealed.
3) A year or two back the original suppler of the square tins stopped producing them so we had to find a new supplier. Despite rigorous testing and guarantees, these newer tins did not seal as well as we had hoped and were not as strong and so as a temporary measure we put in the cardboard inserts while we used up the supply and designed, sourced and received new tins. It can take many months to do this and so we cannot just switch to a new tin in a matter of days.
4) The heat seal is an anti-tamper device to ensure that tins have not been opened. It is not a "vacuum seal". The tins are all vacuum sealed before going into the machine that puts the plastic heat seal around the edge. It is two separate things.
5) The new tins all seal well, although of course no system is 100% fool-proof and many other factors come into play such as how the tins are treated in carriage and storage of which we have little control over.
6) Our tobacco is sold to be smoked and enjoyed. Not necessarily for long term storage.