The scale is defective. Send it back to RCBS and get them to fix it. I cannot believe people put up with these kinds of isssues and just think it is normal.
To the OP., I tried all of the auto dispenser models but not the one you are looking at. I can throw charges with a powder thrower much faster and just about as accurately. For longer granule powder I throw onto a manual scale and trickle the rest, accurate and just as fast. I however charge all cases then seat, if I charged then seated each case the auto thrower would work fine because it will throw the next charge while you seat the last one. Of the ones I tried the one I liked best was the Lyman, but I eventually sold it, the RCBS and the Hornady because I never used them.
I know that the scale is not normal, however I don't think that RCBS would replace the scale. This is the reason that I am looking at a different scale. I will call RCBS today and find out.