My java fern did that for the first few months in its new tank and as this plant thrives in similar conditions, I'd assume it's much alike. I just nipped the leaves off when they got too spotty.
The ph is probably a bit high for it, but I dare say it'll adjust in time. It also has a pretty low tolerance for chlorine exposure, so if it's been in non-conditioned water that might not be helping.
It'll probably start sprouting new, greener leaves once it's settled to the new water conditions. I've read it does much better tethered to wood. Wood will also lower your ph a little (though not so much if you're doing 100% changes.. I don't do those in my heavily planted tank) and since adding the wood, I haven't had any of those marks on any of my fern leaves. It probably will have less effect in 100% change conditions, but it will make moving the plants in and out easier.