I have a recurring problem where I can create a zone schedule and place it on my drawings, however if I go back on the drawing or the zone schedule at a later time, all the information has disappeared but the titles. Any suggestions?
You should have created a view in the View Settings for your schedule, and it is this view that you place on the layouts.
If you have not done this then give that a try.
If you have done this, then check the view settings to see if it has the correct layer combination and renovation filter set - this will affect what is scheduled.