Sunburn or Disease?
So I started some heartleaf philodendron cuttings a few weeks ago and they all rooted, despite being planted in water "upside-down". My question today is unrelated to cutting orientation because apparently for this plant, it decided it didn't matter. Initially a few leaves started dying off-maybe stress or perhaps due to the fact that when the plant had been removed from the store wall by the original owner it had been allowed to go bone dry then left on the front lawn under high noon sun sporting it's free sign. Well, the leaves kept dying one by one whether or not the cuttings had rooted and were actively putting out tiny, new leaves. Then I noticed that there were occasional red spots on the dying leaves. Now it looks like the new leaves have the red spots and are dying, and since those are brand new growth, I'm starting to suspect disease-or sunburn, since I do have them in a bright window-and because I already have a happy, healthy, heartleaf philodendron I don't want to fall ill, I'm considering committing philo-cide and tossing out all these cuttings, new buds and all.
So my question is, in your opinions, does it look like sunburn, or disease?