That does not look like any over watering I have seen.. The leaves look to perky..
My first guess is bugs.. Did you look closely under the leaves.. You should see webs..

My second guess is NUT lock up of some sort... Maybe the wrong PH... Plant can'5t absord the proper nuts cause you ph is all f'ed up?

That is why, it is good to use lots of perlite in your soil mixtures... so you can flush the soil....if you had lots of perlite you can almost always rule out over watering... perlite provides lots of space for roots to get O2.

You may consider getting distilled water from the supermarket.. you may also consider a transplant into a sper perlit mixture.. and MAKE sure you PH is 6-6.5

good luck.. le us know what happens