Belgium 1 Franc 1939: Mint Error, Or PMD? One Of The Weirdest Coins In My Collection

It sure looks like it was struck that way.

Bumping the thread as I got recently reminded it by this recently referenced thread about a vaguely similar error on a US Lincoln Cent from 1944.

That one, AFAICT, was eventually attributed to alloy-related issues. This coin shouldn't have alloy issues (because the alloy is supposed to be 100% nickel), but there clearly was something odd going on with this planchet at the (Brussels) mint.

My best guess, at this point, is that some kind of non-nickel inclusion somehow ended up within the planchet and then, at some later stage, corroded away (and/or fell out). I doubt that the planchet was struck already with the gaps, because then (I suspect) we'd probably have seen a lot more distortion in the design, particularly on the lettering.

If I ever get that coin in hand again, I'll try my best to make close-up photos of all the holes... particularly at 9h on the obverse, where the tiny lettering of the engraver's name directly intersects with the missing part.
Not that I'm confident it would help all that much, given the amount of apparent post-mint crud (and the even larger amount of presumably-circulation scratches).

For reference, because I somehow didn't bother to mention that in the OP: this type is supposed to be 21.5 mm and 4.5 grams.
An exact weight (to 0.01 grams) of this specimen, with its missing parts, would be the first thing I'll try to check if/when I get the coin in hand (even before the close-ups, probably).


EDIT: And a final comment, from a 2022 post about this coin, which somehow didn't manage it to this thread before either...

Defective planchet with possible a Blowhole type error. A Blowhole error on a coin is a type of minting error that results in a ragged hole in the coin. This usually happens when the metal strip used to make the coin is rolled out and tensile stresses cause parts of the strip to tear apart, creating a hole with beveled edges.

Blowhole errors are quite interesting and can make a coin more valuable to collectors due to their rarity