Brown pistils in early flowering?

[GrowInTheDark]

Hi i have 6 plants that are 12 days into flowering, they are 63 days old, grown in potting mix and under 8 100w cfl 2700k bulbs. i give them calmag, and 2-7-7 npk nutes. I noticed that some of the pistils have started going amber/brown on one plant, and i was wondering if this was normal? This seems to only be near the middle of the plant and not the top(for now). P.s the affected plant matured alot sooner than the others.

 

[VladimirPutin]

those pistils are the oldest. sometimes it is normal for them to change with age or it can be a sign of underlying plant issues.
The plants look good though.

Vlad