So it seems even the tins that are sealed now, but were made between Feb/Mar 2018, are more susceptible to easy seal failure. I would think these would need to be watched closely in 6-12 months when tins are supposed to start bulging, so that weak seal doesn't become compromised.
Or is this an issue of whoever is applying the seals is doing so incorrectly? Mine popped right under the tab, and it happened either before it left the facility or in transit. The plastic lid would have had to been removed to see it.