I have been finding ripe berries with holes in them for a few years. The culprits are these little black worms that look like flatworms but don't have the hammer head and are pitch black.
Here is a blog that has photos of them. The only way I've found to keep them off the ripe fruit is to pull the berries out and lay them on top of the leaves. Anything even close to touching the soil will be eaten.
What are they and how do I get rid of them?