Blueberries have a diferant fertilize requirement than other plants and bushes.I think that could be the problem. I dont think it has anything to do with raised beds.

Not wrong to have them in a raised bed, or in compost but you may have to amend the soil to acidify it. Blueberries need a PH of 4 to 5. Here in Nova Scotia, Canada, low bush blueberries grow wild in such abundance that they are exported throughout the world. Our soil is acidic but even when we grow blueberries in our gardens at home and amend the soil with compost, we have to increase the acidity since compost will render the soil neutral. We do this by adding aluminum sulfate in early spring.

Another thing you might look at is the drainage quality of your soil. Blueberries prefer extremely good drainage so you may have to add sand to your mix. They have shallow roots too so don't cover them up too much.

Of course, sun is essential - lots of it.

There is also the possibility that your blueberries were establishing themselves root-wise and did not expend energy above ground this season so no correction may be needed. (I suspect the PH and drainage may be issues though...)