In the event notes, it states:

Dark Matter Arcane Glyptics Campaign

For the duration of the campaign, Geas Fete equipment from Reisenjima can be engraved with arcane glyptics up to twelve times at no additional charge, with the equipment receiving the same benefits as if they were engraved with dark matter.
* Visit Oseem in Norg (I-7) to engrave your equipment.
This restriction is lifted at 8:00 a.m. (PDT) each day and you will be able to engrave your equipment up to twelve times again.
This restriction is lifted at 3:00 p.m. (GMT) each day and you will be able to engrave your equipment up to twelve times again.

When I traded my herculean gloves to Oseem, I was only given 6 chances to engrave.