brittle super curled ~ wavy leaves! help?

This is what i have so far;
Nft gt424 system

Ph is at 5.8
Ec at 0.4
Temp 25/26
Humid usually sits about 50 with wet towels for extra humidity.
Res temp unknown but is neither too warm or cold to the touch.

The issue im having is that with one of my plants im seeing leaves droop curl under and go brittle to touch, im thinking it could be due to the extra humidity from the towles that ive been using since the problem first started - becauae i was thinking it was too dry!

My friend had a similar issue with the leaves drooping due to the extra Humidity He was adding
And his now sits at 30-34 and his plants are perfect. And seem to love it same system ae above.

Ive included pictures showing the two plants in the same tank and the major issue one of them seems to be having even though the other is not having the same problem, please help!
Sorry for the lenth of post

Looks like it's maybe a root issue, I would tear the RW and take a look.

Is your rockwool floating in water or am I seing your photos all wrong?

humidity would also soak into the rockwool ? HOw often to you water? At a guess, that rockwool looks wet - not damp

I think rock wool stays too water logged.

I would say the same. Too wet. I hate rock wool.

I thought it looked wet also but why does the.other one seem happy and my friend also has same system and looks the same yet his are so happy i am using my friends profile he lnows about but tge two of us are baffled

clone the one that likes the environment and get rid of the picky one

when you crush the rockwool fibers it allows less air to pass through and is easier to get waterlogged
you should always be careful when handling it

also you should pre-soak and buffer, and charge it before using it

the roots shouldn't be able to grow out of the cubes, this means you're letting them sit in water too long

If their clones I'm not sure why one would do well and not the other. If their seeds then their needs could be hugely different. But it does look kinda wet, i have never used rock-wool other than 1" cubes to start so not sure if thats the cause. Hope you get it figured!

I thought it looked wet also but why does the.other one seem happy and my friend also has same system and looks the same yet his are so happy i am using my friends profile he lnows about but tge two of us are baffled