I think the thread on CU makes it pretty clear that the defect involved on thenThomas card affected multiple cards. Somewhere in that thread there is a complete list of the cards and even a diagram of the object that apparently blocked the ink off those cards, and it was fairly large.
There is a discussion in another thread here, actually several over time, of what is or is not a variation. One leg of that would be whether something like this was "an intentional change", or a recurring print defect on some print runs, lile the Herrer and Bakep.
Did this error occur on the first print runs of the affected sheet, get noticed, and then was "corrected". Or did it it occur in later runs and then corrected. Does it even matter ? Likely not in this case since the hobby treats it as a variation. And for me, under my personal definition of a variation, it does fit, since it surely looks like someone intentionally intervened in the print process to correct it.
Another example of this type of variant would be the 82 blackless cards. They are listed as a set and not as variations in The SCD Standard Catalog. But they are the same as the regular 82 cards except they lack the black ink. The cards can also be found with grey where the black should have been as the ink ran out. Like the Thomas, the cards were distributed in packs and are scarce. Did someone notice that the black ink ran out and "fix" the problem, or was it not noticed and the ink simply refilled in the normal process. And does it matter for purposes of classification
The Blackless cards are recognized by SCD, but not, as far a I know by PSA. Not sure about Beckett. In that sense they may be like the 62 green tints that are recognized by SCD, but not PSA, and maybe for similar reasons, since there are many cards where they are in transition with grey of faint hints of black, and overall hard to spot without close inspection
I need to stop thinking about this stuff
