Mine too!

Usually because the sheets ball up and all the moisture gets trapped inside the blanket-ball.

Then when we open it up, we feel where the inside is still all wet. So annoying.

That's because blankets are bulky, so they wind up into a ball and the core stays damp while the outside dries.

What you can to is pull it out and shove it back in in a different way so that the wet part is facing outward. Then run it again. It shouldn't take as long because most of the moisture is already gone. Do a third run if you have to, but that should get it bone dry.

And remember to clean your lint trap each time! Blankets drop a lot of lint, and the machine dries faster if the lint trap is clear.

If you have a quilt or something with multiple layers or insulation on the inside, sometimes there can be residual moisture you can't feel from the outside. So either hang it up or lay it out flat and run a fan across it and/or a dehumidifier in the room, and let it air out like that for a couple hours/overnight.