I need HELP!!!

I am very new to home brewing. I just brewed my first batch and bottled it just under a week ago. My first concern is, the first bottle that I filled was a clear glass bottle just to see the color and watch as it self carbonated. At first it looked like there was just a few white bubbles sitting on top of the brew I thought maybe it was star-San but I don't think that's the case anymore. This doesn't look like it is in any of the other bottles, but could somebody please tell me if maybe this is a big problem? I don't want to get anyone sick. Please see picture below
This was the first bottle that I bottled the others are in Amber bombers and 12 ounce bottles and I don't see any of this Residue.

What did I do wrong?

Did you check the beer for final gravity with a hydrometer? Did the FG remain the same for 3+ days?

It looks like it was still fermenting in the bottle and that is hops / kraeusen floating on top.

This can overcarbonate the beer, even causing bottle bombs.

Unfortunately no I didn't check it. I assumed after 3 weeks (stupid me) 1 week in the primary then transferred into secondary for the final 2.

Is there anyway to prevent the bottles from exploding or is it now a waiting game? I am storing the bottles in a dark cool closet. Should I open one up now and test it?

The day I bottled the fermenter had no white foam or anything still on top. I was doing some dry hopping and that had sunk about 90%. I was very careful siphoning it into my bottling bucket.

Thank you so much for getting back to me!

Your issue may be putting it in secondary. This removes the beer from the yeast, and if it hasn't hit FG, it slows fermentation as you are removing much of the yeast.

I would pop one open, see how carb'd it is. You may be fine with that style of bottle, they're stronger than capped bottles.

I will try that, thanks again for all your help. Sadly 80% Of the bottles are crown capped