I think I can see some scale in the top image. If you look carefully and see no scale, look to over-watering.

With no background history of how long you've had the plant? pot have a drain hole? does you home have a water softener? how has the plant been cared for (light levels [especially any changes]? watering habits? soil composition? fertilizing [what with and NPK %s] temperatures, ......) we cant do much more than guess, based on images and the odds.

Al

I've had it for 7 months and its grown quite a bit and put out 4 offsets since I've had it, sso it's been pretty happy up until it went outside a few weeks ago. Yes on drainholes, no water softener. It, along with my +-200 other succulents, were grown over the winter under lights that are designed for growing cannabis. I'm pretty particular about my succulents not getting etiolated while they're indoors.

I haven't fertilized the at all. my watering habits tend to be on the neglectful...but graptopetalum must like that because the plant didn't lose any leaves over the winter, unlike many of my other plants that lost some leaves due to going too long between waterings. However, come to think of it, about 2 weeks after the plants went outside we had 2 days of rain. I wasn't worried about it because I mix my own soil and it's very fast draining. Hmmm...

Why would the worst damage be in the newest growth?

Did they go out into full sun?

Al

A couple days in part sun then into full sun.

If you can remember how the pot was oriented when you moved it to full sun, look at the plant and imagine the sun's rays striking the plant from the S or SW. Does a pattern emerge that shows the most damage to be on the leaves that were facing S or SW? If yes, it's probably sunburn/photo-oxidation. If no, perhaps the period of rain you had caused a root infection, the symptoms of which were made manifest in the foliage.

Al

Another thought - fungal infections often get their start under conditions where moisture levels are extremely high or wet and air movement is minimal. Even if your plant was placed where air movement was adequate or even good, the cluster of leaves in close proximity at the top of the plant creates a micro-environment where air movement is quite limited. It might have been the limited air movement and the extended period of rain that made a fungal infection possible. There are 4 things required for a disease pathogen to infect a plant. There must be an innoculant (fungal spores), a susceptible host (your plant), favorable environmental conditions (rain and limited air movement), and time - fungal spores need a period of constant moisture long enough to allow germination of spores. That's why watering late in the day isn't recommended - because it often ensures plants will remain wet all night, long enough for spores to germinate. I tend to favor that idea over other potentialities I mentioned.

Al

What fungicide would you recommend?

Thank you! Fortunately I have some of that on hand. Appreciate it Al.