White tails and African buffalo are in two completely different categories.
The DGX is not up to a reliable standard for my liking to take down an animal that can & will kill you when given half a chance once badly injured due to poor bullet performance.
Again, why risk it when there are far better options that performs perfectly 99.9% of the time? we owe it to the animal we hunt, to kill cleanly.
I'm not bashing Hornady, I'm glad for all the positive things they do & stand for but not their DGX range, old & "improved" has a bad reputation & that will haunt them for many years.
BTW, I don't think the concern has ever been the hardness of the cup, but rather the bonding as the cup & core tends to separate cleanly & the cup disintegrate...perhaps too hard/brittle alloy causing it to break instead of disforming and remain bonded to the core?
Regardless, if Hornady does correct it, I'd suggest a new packaging or even a name change of the range ie DGXX or anything so people will know its really the improved / redesigned ammunition, but I suspect its a matter of cost. The old stock will be returned at a loss since no-one will want to use it.
To ID the new "improved DGX" ammunitions you have to lookup the serial number and do some funky science times the feeling of the color purple to know if it is the improved stock?
Is this a ploy to fool the uninformed & push it off to consumers to take more risks? I can see the benefit of this. If it fails, they can claim its the old / poor performing stock. if no feedback, no worries, the money is in the bank.
Unfortunately, reputation is always measured on the worst, never the best performance regardless of the cause.
Some pictures of the internal view of a buffalo cow hunted by a friend of mine (Frederik), just have a look at the size of the ribs that overlap each other like armor.
300grn .375 Woodleigh HD, bullet was found just under the skin on the opposite shoulder, perfect performance delivered from a quality bullet.