Do you have other crafting profession on that second enchanter from which you got first time craft exp? Or maybe you got that exp from other enchants?
Total amount of first time crafting experience you can get is limited per char. It’s entirely possible to run out off first time crafting exp if you have 2 professions - i don’t remember the exact number, but from my experience if I started crafting at 78, I could reach something like 79,4 with just first time crafts.
Limit was actually always there. In the beginning of Dragonflight it was 60 crafts, but then in December 2022 they reduced it to 30.
From the patchnotes
The number of first-time crafts that can grant experience has been reduced to 30 (was 60).
Developers’ note: We made this change to better support gaining XP from crafting during leveling, while minimizing the incentive to take on several throw-away professions just to level yourself faster."