I received a "private message" (via FT) from an AA agent. [AA does read this forum^]
I supplied my locators for the 3 itns which for which "print trip AND receipt" is missing. Their explanation (which I just received):
(1)One trip was booked via AA-VACATIONS
(2)One is an AWARD ticket
(3)One is wait listed for an SWU.
These don't allow printing receipts (directly) from AA.COM.
[For (3), when my w/l is confirmed, I'll be able to print the receipt.]]
So, in my case, there is NO "glitch".
I have three AA award tickets, booked in March, July and July. I have PDF copies of all three Print trip and receipt from each booking, after they ticketed. Two of the three reservations had changes from the recent set of schedule changes, and again was able to print copies of the updated Print receipt and itinerary. This option remained available on all three reservations until just a few days ago.
Definitely a glitch, or maybe its 'hiding' like when the view available seats function went away from the main menu options.