Over watering or under watering, it does not like being a pot. I suggest planning in soil or ask in the container gardening forum.

I've grown Camellias in pots for years, a couple have been happy in the same pot for a decade, but I switch out the soil and check the root system every year or two. What growers grow in nowadays is the cheapest junk the plants will tolerate.

Try repotting in a quality acid mix and when the weather cools down in fall give a few very diluted hits of acid fertilizer. Give the plant full shade for a few weeks to recover. Keep moderately moist at all times but never soggy. Make sure the pot has an AIRY fluffy mulch that does not compress. Do not replant deeper than the original level.

Camellia root systems want air but at the same time constant moisture and cool temperatures. They will either dry out or suffocate. You have to walk that line between the two. If you can do that they will be happy, as they don't need much besides a cool, protected root system.

Being an understory plant, they must survive despite being in soil robbed of most nutrients and water by larger trees. Make sure the roots are shaded. If you take care of their small, sensitive root system, the rest of the plant takes care of itself.

Thanks...I'll move it to a shadier location for now,and repot when we've seen the end of our hot weather.

I really think your problem is that the potted plant sits inside of a planter which I presume does not drain water. Take the plant out of the planter and leave in a pot that drains. For cooling you may want to insert the potted plant inside a much larger clay pot and fill in between the plant's pot and the side of the clay pot either gravel or bark which you can water down to get wet. This will help keep the plant's roots cool inside its pot even though your plant gets SOME direct sun in the day. I am in Zone 9b and I have a camellia plant planted in the ground, that stands about 8 ft tall, sitting at the SE corner of my home where it gets full sun from early morning into mid afternoon. It is surprising to me that it survives there. I try to wash down the soil which is shaded by its lower leafy branches once a day.