[2023] There is now a grace period for 120 Necro for comp cape

This is intentional!

On release, the 120 Necromancy achievement had a grace period but this wasn't being accounted for in the 'Completionist Cape' achievement, but was being accounted for in the 'Master Max Cape' achievement.

In the latest update this was fixed.

I'll look to get the news post/patch notes updated.