that really looks like one of two things to me, maybe both. large ph swings can cause patches like that, and root rot can cause patches like that.
you're checking the ph of the water you water with, after you add nutes to it (if you're adding any) and its 7.0?
thats not too bad for soil, a little high, i'd suggest a nice slow swing up and down between 6.5 and 7.0, centering around 6.8.
keep an eye on your new growth tips, and all your leaf edges. if those look ok, i'd say its some kind of ph problem. if they start to show damage, you might have root issues.
related to both, how often are you watering? are you letting your soil dry out good between waterings? are you using soil? hard to tell from your pics.