The spreed sheet in Quattro Pro X8 will not accept a change in the footer setting. Probably in a Windows update the date format is changed to #d and I like it to be #D. What to do? The general date setting is the long version.
I just tested this. I created a footer with #D. It worked fine. I then changed the footer to #d. It didn't work, but preserved #D as the footer. Several repetitions resulted the same way. I then changed the footer to #f. That worked. I then changed the footer to #d. It worked then. I reversed the workaround and changed the footer back to #D.
I therefore confirm this as a bug. Probably, some line of code erroneously fails to distinguish upper- and lower-case letters when deciding whether the user made a change in the settings. Try the workaround I found and see if it helps.
When marking #d and then retyping over the marking with #D it worked.