When you move a plant to a more sunny situation, it could take 2 weeks or more of slow acclimation. I believe I said more sun (not full sun) and slow acclimation.
My stapeliads live in a south facing greenhouse were the temps often get over 100* (today, it was 103* in there). When I introduce a plant to the menagerie, I put them in the shade for a couple weeks before moving them to a dappled sun position on the south wall. The dappled sun is created by large cacti that can take full sun.
BTW, I grew up in Sacramento, graduated from Stanislaus State University and lived in Modesto for several years before moving to Oakdale for the last 30.
Daisy