USA #CVP91b - blue color printing variety (most likely due to doctor blade)

Description

USA #CVP91b
Printing variety due to doctor blade problem on the blue ink color
The USA "CVP" stamps using the pre-printed designs have rarely ever had any sort of errors & printing varieties on the pre-printed design portion of the stamps.
However, at one of the Plano, Texas "SSK" (self-service kiosk) machines, a printing variety has just been found.
While the USPS doesn't state what printing method is used for printing the pre-printed portion of the design (ie: the flag design), given my past experience in the printing industries, and the nature of the error/variety, I would say that these designs are printed via gravure (engraved/etched) cylinders.  In gravure printing, the ink flows into the recessed areas of the cylinder and a "doctor blade" then removes the excess ink on the cylinder, leaving just the ink that is to be transferred to the paper in the recessed pits.  The ink is the transferred to the paper.   HOWEVER, if there is any ink left on the printing cylinder on the non-design portion that didn't get removed by the doctor blade, it would also get transferred to the paper.
--> Given the overall "look" of this, it would appear that the doctor blade has a problem of some sort especially near the edge of the design (could be anything from the blade not being completely straight to being damaged, dried ink build-up, to perhaps not enough pressure), causing some of the ink to end up on the non-design area of the cylinder.   Only the blue color seems to be affected by this, the other colors used to make up the design appear to be ok.
Again, based on my knowledge, having worked in an industry where printed using gravure cylinders, this does NOT appear to be a problem with the printing cylinder itself, but instead with the doctor blade that wipes off excess ink!
Please note that other printing methods include "lithography" and "flexography", however, the error/variety shown points this at being gravure (a form of intaglio) printing.
This lot consists of 2 stamp strips (as shown in the scans):
A strip of 2 (1 stamp & 1 VOID label) with the printing variety purchased on June 30, 2021
A strip of 2 (1 stamp & 1 VOID label) without the printing variety, purchased on September 27, 2018
The first image shows a close-up of both variety & regular stamp so that you can see the difference, the 2nd image is of both stamps that you will receive.
Both stamp strips were produced by the "new" kiosks that were introduced starting in late August 2018 (and you can tell this by the fact that with the new kiosks, that the sideways human readable code begins with a number, whereas with the original kiosks, that code always began with a letter).
The one thing that we do NOT know for either stamp, is when the pre-printed labels themselves manufactured.  Each box of pre-printed labels (before the machine adds the matrix code, the "FOREVER" and the human readable serial number at the time of purchase) will have a label on it stating the manufacturing date.   But, one would have to have USPS personnel open the machine up in order for us to see what the production date of the labels was, and rarely have I been able to see this...
--> Another item to consider:  when the new kiosks were placed into service, the CVP91b design was supposed to be replaced with the CVP108 design.  However, some post offices may still have some of the CVP91b labels in stock and are using them up.  Here in the Dallas area, this is the only machine that I've seen recently that has the CVP91b labels in use, all other kiosks are using the CVP108 design.   --> So in addition to this being an interesting variety, it also represent "late purchase" of this design!
So, if you are a collector of USA ATM / CVP stamps and/or like collecting printing errors & varieties, then this will make a nice addition to your collection!
You will the receive both stamps shown.  I have put together 7 sets of these (1 each regular & printing variety) as strips of 2 as shown in the scan.   If you are interested in a full sheet (of either 9 or 10) of these errors, it might still be possible for me to procure them.
As a specialist collector of these stamps since 2012, I find this to be extremely interesting, as most errors & varieties regarding stamps have been with the "thermal printing" that the APC/SSK kiosks add, NOT the pre-printed portion.
I will only mail via tracked mail within the USA and untracked mail (at your risk) for foreign shipments.