This Machine has a mind of its own. Every time the customer puts the original in 11x8.5 it prints it on 8.5x11 cutting off half the page. I have replaced the original tray sensor and thought this would take care of the problem but no. any ideas? Thanks in advance

Do you maybe have the " Auto rotation " feature turned off? Other then that, maybe clean the D.F. original tray guides, sensors, and sliders on the under-side of the original tray.
HTH
Brian

I have had one of these where the firmware sim had to be replaced. It consistantly fed the wrong sized paper on auto rotate and auto detect.

Is there a floresent light right above the copier. Try it with the lights off.

I've found the ADF tray guides can read landscape if even a few millimeters shorter than 11 inches. I use a little triflow so they guides slide right next to the paper and inform the customer that it's a little sensitive so make sure the LCD says the correct original size

I've seen quite a few DP-410 do this and there is nothing to fix (in my cases). The paper detection doesn't happen quick enough and the user hits the print before it occurs...size mis-selection. Watch the display and try it yourself, press print fast, then slower. It may be related to the original orientation and default drawer orientation. By instructing the cust to pause momentarily fixed my situations.