Starting after printing that file 2 more times: once portrait, once landscape
[root@coyote Documents]# ls -l /var/spool/cups/ |grep d
-rw-r----- 1 root sys 16775 May 13 06:41 d00655-001
-rw-r----- 1 root sys 16782 May 13 12:27 d00656-001
-rw-r----- 1 root sys 16775 May 13 12:28 d00657-001
[root@coyote Documents]# head -3 /var/spool/cups/d00656-001
%PDF-1.4
1 0 obj
<<
[root@coyote Documents]# head -3 /var/spool/cups/d00657-001
%PDF-1.4
1 0 obj
<<
Looks identical to me..
Okular, file 656 is done in portrait mode verified by adjusting the shape of the okular window until the scroll sliders just disappear, it also line wrapped the text. By the same mechanism, 657 is being shown in landscape although this draws attention to the fact that this LCD monitor doesn't exactly have a square pixel. Minor detail, I am used to it.
"cupsdisable Epson_Stylus_NX515" gave no return status at all
Powered it up, no print, sitting idle
[root@coyote Documents]# /usr/lib/cups/backend/usb
DEBUG: list_devices_libusb
DEBUG: usb_find_busses=2
DEBUG: usb_find_devices=15
direct usb://EPSON/Stylus%20NX510 "Epson Stylus NX510" "Epson Stylus NX510" "MFG:EPSON;CMD:ESCPL2,BDC,D4,D4PX,ESCPR1;MDL:Epson Stylus NX510;CLS:PRINTER;DES:EPSON Epson Stylus NX510;CID:EpsonRGB;" ""
cupsenable Epson_Stylus_NX515[return]
all 3 jobs came out of the printer, with 1 and 3 in the landscape mode, the printers display says it needs cyan ink, and apparently kwrite added a header line above the text, date at borderless left, and filename centered. A pageno was on the right for portrait, but where the line of text wrapped in portrait mode, in landscape:
... in length so that I I I I I I I |end of paper
So something, somewhere, went out to a "6 martini lunch" at the 90th or 91st column.
At the bottom of the page in portrait mode, it attempts to print the files url, right justified
But the landscape version has file:///home/gene/Documents/Doc Doc Doc Doc Doc Doc
with the left bar of the D clipped off in the duplicates, and in both cases the bottom 1/3 of the text is clipped off by about a .1" border enforced someplace. The printer itself in doing color photo's, can in fact do a 'full bleed". I can, maybe, depending on the reach of my scanner(s) scan them and put them up on my web page but that will take some time to edit the links to work. This NX515 has a built in scanner and there is an older 1250u available too. Both will need excavating to operate their lids, this room in the middle of this 1970's tract house, designed to be a childs bedroom is best described as a "midden heap"

In 22+ years it gets deep.
Finally:
[root@coyote Documents]# service -f cups
Stopping CUPS printing system: [ OK ]
Starting CUPS printing system: [ OK ]
Re-enabling disabled print queues:
Looks totally normal.
Thanks again for your interest, it seems the driver may have a problem, and that changing the driver to the simplified one partially solved that, however there are problems yet to solve.
Additional data point as I didn't recall if the okular display was similarly clipped, so I turned the printer off, re-printed the file from kwrite in landscape mode, and viewed it with okular, which for some reason behaved better this time in that it shrank the displayed page to fit its screen window, and that view is perfectly normal. No line wrapping problems at the 90th character, or clipping of the top header line. Zooming in to take a good look at the bottom, footer line, it is clipped at the pixel above the baseline, so the bottom row of dots and any descenders are missing.
This clipping, because FF also adds this stuff, being clipped off makes the URL's a guessing game.

OTOH, this is not the same problem.
I have been on the gimp-print list since forever but dropped off once my beta testing for the C82 support was over, and I could probably rejoin and make some noise there, which might lead to an eventual fix in 5.2.8 if I do it quickly enough. Recommended I do so?
Thanks & Cheers, Gene