My indoor desert rose just started doing this this week also, havent changed a thing: water only when completly dry, use a chopstick to see if its damp, AC daytime 75 and night 73, indoors w/southern exposure now (afternoon sun) this was the only new move I did thinking maybe it needs more sunlight. Since i had it in low light before but not sure why my leaves are doing the same as yours? Hope someone answers and for potting mix I use the gritty mix. which calls for more frequent watering than normal but I normally only water 1x or every other week now. I guess I should go back to watering it 1x a month? When I was doing this the leaves didn't change yellow or start to brown on the edges.

pic of its new location in southern window but my other (far right) white angel desert rose is doing just fine. I got this one May 2013 bareroot and this gets water infrequently only thing is the bud that was going to form dried up and fell off. Guess I need to water this more. But I moved the (left) plant here so it can get more sun and I had that one sine Mar 2013 which I had to prune it back do to the leaves since I bought it from lowes all fell off. Transplant shock, now it grew leaves back, but this week the leaves are changing.