Is this a deficiency?

Ok, so I decided to just just grow 4 autoflowers packed in a small grow room. Just a little experiment. So one of the plsnts, Bubblegum kush has some leaf problems. At first I didn't think too much of it, but in 2 days it turned bad and quick.

I think I was giving it too little bloom nutes, could it be because of that?
I also raised the lights.

I'll post some pics of when I first saw it and 2 days later

Looks like Potassium (K) deficiency.

In other words, yes too little bloom nutes.... ONLY IF your PH is on point.

Your plant is eating calcium from itself. Overall it looks deficient though.

Wtf is this!! I fed the more nutes, it's not helping. The plant looks like shit, what do I do??? The other one are starting to look the same

Your not giving enough info? It's ph or salt build up,cal mag prob. imo. Flush the lot with plain ph water to 6.5 if in soilless. Three times pot size. Then feed them your normal nute regimen, give cal mag too. This should stop the spread not cure leaves. Make sure your ph is correct always. Some strains hate fluctuations

look at calcium and manganese deficiency, like tiltswitch said not enough info, I just happened to be looking at ILGM leaf deficiency's chart and spotted it. Your plant is looking like crap is because you haven't taken care of the problem yet, new growth and middle is where it hits hardest and the other leaves haven't showed the def yet but are starting to, those 2 elements are either locked out as tiltswitch said or not in your feeding, foliage spraying is for quick action try that until you find out what causing the problem in your medium. hope this helps good luck