Necromancers just can’t catch a break! Well, minion ones anyway, the Blood Wave spamming fellows are doing very well.
Today’s patch was supposed to fix the 
Ring of Mendeln, but as players became aware and started reporting, it didn’t quite do a thorough enough job. There’s a big list of things that aren’t interacting with the ring properly over on the official forums. Blizzard are working on the problem and think they’ll be able to fix the issues via hotfix.
Hi all –
Team is working on addressing the slew of items still with Mendeln. They met this morning and it seems like a smaller scope of fixes were hit but not all of them as detailed out through a bunch of investigation from the community.
We are looking at the rest and based off initial takes, it may be something we can do via hotfix. We will know more once the team dives into it some more. This means we can probably get the fixes out a bit sooner unless we find something that will require a client patch.
Separately, some of these are tied to some tooltip errors which will be addressed in 2.1.3 as tooltips typically require a client patch but we believe after the changes, the actual engine and underpinnings will be working. We will be thorough with the tooltip items to help clarify whether this lands in a hotfix or emergency client patch.