The #1 reason why you have the problem you describe is that there is something sticking up from the bottom layer of dishes that is causing the spinner underneath the top layer of dishes to stop from spinning. The whole cycle will run through regardless, but the dishes will not get cleaned properly and you will end up with a half dissolved tablet still in its little box.
So it is always important to check the spinners after you have loaded the dishwasher. All you have to do is reach in and flick it and if it doesn't freely spin all the way around, look at what is stopping it. Usually it will be a wayward plate that is a wee bit too tall in the slot it is in, or maybe a pot handle that went a little higher as you rolled the tray in.
Sometimes the spinner thing gets pushed in so that it is flush against the bottom of the tray, and that can cause a problem too. Just pull the tray out and give the spinner a wee tug at the base of it, you will feel it pull and snap into place. Then flick it for a test spin and you should be fine.
I have never known a dishwasher to not 'bake' food that didn't get rinsed off before the dish was put in the washer, which to me always seems to defeat the purpose of a dishwasher but there you go. Anyway, if you are having a problem with food still being stuck on the dishes after a wash, the simplest solution to that is to be sure that all food is wiped/rinsed off any dishes before you put them in.
Hope this helps. If you are still having tablet problems after you've cleared the spinner issue, I don't know what it could be. But it is probably a plate or something getting in the way. I put all my tall plate on the outside edge for that reason, it helps. After a bit of time things inside the dishwasher aren't level anymore.