I'm not sure if the digital version of the book you have on this website is the latest errata, but I just noticed some discrepancies.
What I noticed is that on the digital book (on the table) Grumink the Renegade has CR4, but on it's monster page has CR8 (Probably coming from Assassin).
On the table, "Ghald" has CR5, however later on that page on it's monster block, it is stated CR7.
I corrected Ghal's CR as it is a CR 7. But, I don't know about Grumnik. In the book (latest printing), there is the same error. For now, I have to leave it as it is.
Grumink the Renegade's CR should be 4 as stated in the book.
On this table, Ghald should have CR 7, as stated in the book.
Did you check those numbers against the latest errata?
I'm not sure if the digital version of the book you have on this website is the latest errata, but I just noticed some discrepancies.
What I noticed is that on the digital book (on the table) Grumink the Renegade has CR4, but on it's monster page has CR8 (Probably coming from Assassin).
On the table, "Ghald" has CR5, however later on that page on it's monster block, it is stated CR7.
I corrected Ghal's CR as it is a CR 7. But, I don't know about Grumnik. In the book (latest printing), there is the same error. For now, I have to leave it as it is.