Why do my blueberries shrivel up right before they get ripe or right after they get ripe?

Might seem like an obvious answer, but are you giving them extra water while the fruit is sizing up? Most fruits need it, especially in hot weather.

Deep watering early in the morning will help keep the leaves and berries well hydrated. Check the water penetration using a stick a foot or two away from the bushes, to see if the water you put on has gone down good and deep, not just wetted the surface of the soil.

@dyzzypyxxy thanks for the response to my question. Now that you mention it it does seem obvious the two bushes that have the shriveled-up berries are just two-years-old not established yet. My other large bush the berries are doing just fine they have more roots. I imagine it's too late to do anything about it this year since they are full of berries I'll have to remember that for next season.