I'd be interested to know where you heard this. I don't really see why Content ID scan immunity for managed partners would need to be removed, since so few people even have it, as you need either a CMS account, or to be one of a tiny minority of top people in a MCN's CMS, if that MCN even makes people managed. Content ID is partly in place to stop YouTube from getting involved in a law suit, and considering only very trusted partners have Content ID immunity, I don't imagine YouTube paranoid about them getting sued due to any of them.
Also, with the amount of fraudulent claims, I can imagine top YouTubers being hit by many fake content ID claims if this were to happen, since the person who claims the content has a whole month to accept the appeal, keeping a month's revenue.