Sunscald usually leaves leaves light tan or white. I don't see that in these pictures. In fact, it isn't completely clear what the affected leaves look like. Description? Lack of water results in wilted green leaves. Overwatering could cause browning or yellowing. When you overwater, the roots basically drown, and the leaves can't get the needed oxygen. Perched water in a container will do that. If the soil is moist, you shouldn't be watering.

Sorry, just realized it's very hard to see on the previous pics since I took most of the affected foliage off. It starts off as faint yellow with brown spots and then turns white and very brittle as seen below. It starts at the tips and goes deeper into the leaves. I may have overwater these past couple of days because we have been going through a heat wave but for the most part of the last 3 weeks I have let the soil become fully dry for a few hours before watering again.

Thanks. That does look like sunscald. But be careful about overwatering. What is "strong sun"? Sun is sun. It isn't weak or strong. It's just sun. Maybe you have very high temperatures when the plants are in the sun? Maybe very low humidity? Some protection may be in order.

If these plants are eventually going to sit in full sun, you might as well just kill off the leaves that aren't going to make it!