... could be a little N defc. starting, plus it's a heavily shaded leaf,... As for pH, likely not with no other issues showing, so far,... only a direct measurement of the in-pot pH can tell that tale though! If you can, get the Accurate 8 soil pH probe for this, otherwise, it's the sucky run-off test and calculation, an inferior method, and no need the stress the plant with that with minor symptoms like this,....:smoking: