I got a exlated relic that had only one affix on it and 3 affix only allowed. Offline mode.
Pretty sure you can get a second prefix once you ADD the first one.
This happens fairly frequently actually. If it’s low FP I’ll usually just slam a Rune of Discovery on it on the off chance it gives me something good. If it’s high enough FP it makes for some good targeted crafting if you get one or two lucky breaks on your first add.