I'm on the Project Stream version
After completing an engravings challenge to the max level, the engraving disappears from my list and I can't use that engraving anymore.
This happens to both weapons and armor
I've attached a photo showing head gear engraving list missing things like +assassin dmg, +warrior dmg, +hunter dmg
I forget what others can be on the head but I'm also missing things like +walking speed while crouching, +adrenaline after assassination
Also included a photo of a previous head armor that had th level 4 engraving that I could use before I maxed it and lost it
Engraving list: https://i.imgur.com/98ibYlx.png
previous enhancement: https://i.imgur.com/QzUTrX1.png
For me it seems to happen on all the engravings that you can level up when they reach max level. They totally disappear from every list, including the blacksmith and in the inventory, in both unlocked and locked engravings, the ones I've maxed are totally gone. The legendary ones seem unaffected.
I'm also Project Stream and also experiencing this.
I haven't checked to see if every level-based engraving is gone (probably), but noticed that sometime in my late 40's my crit chance and crit damage engravings disappeared. They are not even listed in the inventory engravings collection. I am level 50.
My legendary engravings are unaffected, and it seems like my ostraka engravings are also fine (none of those are maxed out). I am not sure about the engravings that upgrade by doing something x times, I'm not sure I have maxed any of those out or not.