Is not as much a problem as it seems, if the (5 or so) wine bottles that I routinely carry in my checked baggage on return flights are anything to go by.
(Tip: put base of bottle in heel section of sneakers so that it stands upright when dragging the suitcase around; remaining bottles on top of front part of sneakers; wrap each bottle in T-shirts, shirts, shorts, etc; cushion ends of suitcase with rolled pants or jackets).
As far as MdC is concerned, there was a report that they switched to plastic containers, even though I am still finishing the glass jars my 2015/2016 order came with.
B.