Why can't I duplicate pages today??

I need consistency for my students so they have a routine.   Two days ago, I was able to create duplicate pages, assigned on different days.

TODAY, I cannot.  I can't duplicate.  I can't create a new page with the same title - the system is overriding and putting -2 or -3 after the title.

I had no problems with duplication on April 13th.   What has changed?