Sounds like Plum Curculio damage.

Thank you, will look this curculio up.

Plum Curculio. Brown marmorated stink bugs like to attack hard green fruit too here where I live (Maryland - more or less the epicenter of BMSB population). PC is the likely candidate, but BMSB stings/bites are what I've seen cause those coiled amber sap formations. They look like a pigs tail. BMSB makes a piercing hole and sucks the juices. PC saws into the fruit when forming and inserts eggs into the fruit, so it could be emerging PC larvae. I forget about the PC lifecycle so I'm only guessing there.
Less than 30 min. ago I just sprayed a plum that was covered with BMSB. I sprayed a Bifenthrin and Zeta-cypermethrin combo.

Well it isn't the plum curculio.
And I'm not sure we have those stink bugs here. There's a few little ones in the raspberries but seemingly a different species.
I've seen this 'disease' for about 10 years here so it shouldn't be too hard for me to figure it out.