Firstly, the additional shares that take JPM to 15% were already held prior to the MIN transaction. The holders notice discloses trades in the normal course going back to October last year. They didn't see the need to divest those prior shares.
Secondly, given the ChrisGina relationship, I would be surprised if MIN sold to just any old rogue.
Finally, the 15% provision in the Transaction Agreement can be relied on if the Bidders think it necessary or simply waived if they remain comfortable with the new holder. Every indication so far is it's business as usual.