Please forgive me.
It's more than 5 years, but I remember reading reputable reports that some loads with soft nose HP would launch the core and then leave the jacket in the barrel. I can't remember details of whether it was a hot load or a soft load, that's not the way my brain works. I remember a "flag", then research the details when needed.
I know this to be true because there is corroborating evidence in some older load manuals.