Just a heads up - in v2019 an additional header was added to AP Aging Report.  There are now 2 headers.  

Page header f and Group Header 2

If you do NOT have divisions and run the report sorted by the default Vendor Number, both headers are suppressed.  I've reported the defect and assume it will be fixed.

But in the meantime, no, you're not crazy if you have no division and don't see report headers.