Black Bolt’s Provocation Cap

Sarkhan_Unbroken

Greetings

I’ll keep this short and sweet.
No where under the description of Black Bolt’s awaken ability states a limit or a cap. However, his Provocation seems to stop at 15 buffs of fury and cruelty and does no stack any further.
Can anyone explain as to why this is happening?
Thanks

Eb0ny-O-M4w

The synergy caps his offensive buffs at 15. It was stated when medusa was introduced