Can you describe the design of your layout from which you are printing in detail. Is the form on which you are printing a pre printed form or is the "form" a background image on your layout?
So the form we are printing on is a pre-printed form, this form has some check boxes but is mostly line fields for first name, last name, account number and so on. The forms from my understanding are pre printed in some kind of special ink so they can be more easily scanned and so creating the form as a background img. to print is not an option.
My initial thought was that they were printing using a cheap printer where the paper was not fed in with consistency either due to the use of a cheap tray or just a bad feeding mechanism and this was causing the forms to print correctly at one moment while the entire thing was printed with an upward or downward shift the next time they printed another batch. I later determined this was not the issue after I got the same result using a number of other printers (some quite expensive and precise).
Unless you have sliding enabled on some fields or some objects with auto-resize anchors other than "top and left" set, I see no way for FileMaker layouts to change like you are describing. Like you, I would suspect that the printer is either out of adjustment (we use dot matrix printers and have to frequently check top of form settings and adjust them), or your pre printed forms are not consistently printed on the paper stock that you are using.
Thanks for your help, I will compare a few forms, I didn't think to ask if they were ordering the forms from the same vendor every time and so it might actually be the form itself that is not aligned correctly for every batch print.