Description: The legendary staff uses this bug with the arcane mage, since the double hit does not come out.
How it should work: The blow of the staff should appear in the details addon but nothing appears, unlike the fire mage if the damage done by the staff appears.
The proc effect doesn't add a new spell ID to direct spells. You are getting confused with the DoT version which would create a new spell ID(arcane) of said DoT.
Description: The legendary staff uses this bug with the arcane mage, since the double hit does not come out.
How it should work: The blow of the staff should appear in the details addon but nothing appears, unlike the fire mage if the damage done by the staff appears.
Database links: https://imgur.com/a/1oxqaUd
details of both branches with the legendary staff, there you can see that the damage of the staff does not appear in arcane