Issue with new growth?

[Greenbob]

Hi all! First post here (other than into post). Ill give you a little background on my plant brfore i hit you with issue.
1. My soil is a cheap top soil and a bag of miracle grow 6 month slow release stuff. Ive added no food just water.
2. My plant is 7 weeks old and I believe its just showing signs of flowering. Species is Big Blue (Big Bud/Blueberry) auto flower.
My issue is in some new growth on tip of a branch. There is some dark purple/almost black on the tiny new sprouts. None of the other new growth has this. I'll post pics of plant and some random new growth sites that look good then show you the spot in question.
Heres the plant. 7 weeks old....

Heres some normal (i think) growth....

OK.....HERES WHAT WORRIES ME....is this just purple leaves or something far more sinister?

Thanks for looking :)

 

[Jack og]

Dang someone else had this same issue, stems show need for phosphorus and potassium since u have fed, but the tips purpling like that... genetic? Dunno it’s a mystery we all be stumped on

 

[Greenbob]

Thanks! I found the purple disease thread.....I see im not alone :( Think im gonna snip of affected area....possibly whole branch and hope for best. Ive had grasshopper prob last couple weeks so that thread opened my eyes to a whole slew of issues I never would have thought of. Its intimidating kinda as all the technical jargon is way over my head. Whoever writes the book "Kill purple disease for dummies" is gonna be a wealthy person lol.