I could be way off base here, but the pics make the leaves look mine w they are older & tired, towards the middle of flushing. I'd say they are hungry, though perhaps high ppm or wacky pH in medium could be responsible...?
The soft curling downward of the whole fan leaves indicate a P issue, along w some of the purpling of the stems/leaves. K is usually shown in my garden by the soft burning of the leaf tips & edges. Can't tell too clear from the photo's but this is usually combined w the fringes of the leaf blades raising upwards slightly... can't transpire properly/deal w the heat due to K issues. Some light spotting randomly throughout the leaves also comes w this. Perhaps some other minor deficiencies as well.
It also looks very crowded (no trimming) which will add to issues of air circulation and light penetration. You can actually see that one leaf starting to die back in the middle-right of the pic... usually happens on my lowest most leaves as they become hungry + are lacking light.
Just another pair of eyes to add to the confusion brother! ;-) peace.
