Vishay ceramic disk caps have had a bris courtesy of Mouser.

[22uf]

Please help me understand.

?!

[Greg Robinson]

Spark-gap capacitor. Will breakdown across the gap somewhere above its max sustained voltage rating.

[22uf]

Ahah! That makes sense. I learned something. Cheers.

[g1]

Datasheet attached. Was a gap-cap what you wanted? It probably won't matter for you, but in certain extreme environments it might be a problem (possibility of spark).
Did it come up on a regular capacitor search on mouser website?

[J M Fahey]

Maaaayyyybeeee it works as advertised but it STINKS of Manufacturing Defect being advertised as a "feature".

[Enzo]

I've seen those for decades. If it is a defect, it is one that the cap is physically designed to have. Note the extended shape to the part.

[Jazz P Bass]

I've seen those in my Fluke meters.
Interesting.
I never knew exactly what they were for.

[Helmholtz]

They provide overvoltage protection as specified in the datasheet.
Looks like a useful feature.
Might be used to protect the OT primary in a Zobel arrangement with a series resistor.

We sometimes used a slotted PCB as a spark gap.