Should I be concerned?

Just starting my fourth week of flowering on my first grow. I'm assuming this is nothing but I've read so much about bud rot that I had a nightmare about it. This morning I was checking on the girls and found the tips of the pistols already turning brown. Is this normal or a bad thing?
There's only 3 or 4 heads showing this.

Sorry. Here's the pics

Ignore: Not normal, no. Likely early nute burn. You're using solubles?

Pics and grow info, if you want accurate info and good responses.

Edit: pics arrived, and I reread. That looks fine, some stigmas will brown earlier than others. If you got anything on them, like spray from anything other than water, that can cause browning too.

I've been following the fox farm schedule. Except last week I cut out the grow big completely because some leaf tips were drooping. I also haven't reached full strength on the tiger bloom yet, I'm at 3/4 strength. And I water with just water every other feeding.

Yeah, sorry, I amended my post. Read your question wrong and pictures hadn't arrived yet. You should be fine, looks good!

Its normal for a 7-8 week strain.