USA #CVP91 upside-down printed ERROR stamp used on #6¾ cover from 2017

Description

Upside-down printed USA APC stamp, Scott #CVP91 used as postage in 2017
This ERROR APC stamp was bought & used on October 7, 2017.
Since APC (and other PC postage items) do NOT receive a full-length spray-on inkjet postmark, the cover received the "short" form of the spray-on inkjet cancel (the main reason is that the inkjet inks will smear on the fairly slick surface of the APC stamps).
The cover was received 3 days later.
These upside down errors do occur on occasion, and they are due to the fact that the USPS personnel that services the APC (automated postal kiosks) in post office lobbies put the stack of labels upside down, necessitating that they're rotated by 180 degrees in order for the stamp side to be facing up.   The flag design is pre-printed and the machine thermal printer then adds:
the barcode
the word "FOREVER"
the human readable "serial number" (which is technically the machine id + the date/time sold)
This particular machine was located in Garland, Texas.
All mail in the DFW metroplex is then sent to the "North Texas" mail processing facility before going on to the final destination.
Nice modern postal history item showing usage of an APC error stamp; apparently no one at the USPS noticed that there was something wrong with the stamp.
Note: the cover will be mailed in a larger envelope with a stiffener.