Off Color 3863 Athens Olympics 2004

Good Day.
I searched for this stamp to no avail here.
I, like many, have inherited a collection.
I came across this stamp, cancelled with a note attached, reading "Do not soak this. One off - color will come off!"

I've looked online for color variation of this stamp, as well as looking online at other stamps of this number, but I can't discern and color difference that would result in the enclosed note.

Any ideas?
Thanks.

There is a footnote in the Scott U.S. Specialized Catalogue indicating that the ink on this stamp will crack & flake off if soaked in water. It is one of the many modern self-adhesive U.S. stamps that are considered to be non-soakable.

But most USA stamps, even if non-soakable, do not flake when soaked in water.
So the "One off" may not be referring to the color, but instead, referring to the flaking if soaked.

Ahh, guess this would be a good place for correct comma placement! As I re-read the note, "Do not soak this one off -- color will come off". With your comment @JLLebbert, it would correctly read "Do not soak this one off [the paper]. The color will come off." rather than this is a "one off" unique stamp. Thanks.

Reminds me of another misplaced comma:

Let's eat Grandma.
Let's eat, Grandma.
Commas save lives.

nice coincidence, just found this stamp today :)