I have two very large succulents in my backyard in Southern California which are sort of centerpieces of the garden. Today I found massive damage to the leaves on the left side of both of them (see photos) and do not know what the cause is.

I put down a new layer of mulch with some fertilizer underneath four days ago, and there was no change after that. But didn't water them until yesterday, so I'm thinking the damage could be a result of too much moisture/ over-watering or possibly burns from too much fertilizer. But both seem strange since I didn't use that much fertilizer at all and didn't think I watered more than it would have gotten in any rain. Perhaps the added mulch keeps the soil too moist?

It was also about 90 degrees today and full sun which was a bit of a shock since its been closer to 70-75 degrees most days.

I bought the house with the backyard about 2 months ago and have been reinvigorating the garden. It was previously full of weeds and most likely was mostly ignored by the previous owner. The succulents seemed to thrive with the lack of watering though.

Does anyone recognize the leaf damage or know what the cause could be? I also am not aware of the species of plant either. They have the large leaves you see plus woody stems that are around 3-4 inches thick. The first one has a very long stem (about 3-4 feet which snakes along the ground.

If anyone can help it would be much appreciated!!!

Thanks!