Probably a good idea to dig it out and separate it from the bunch. I've only dealt with mealies and these definitely look like something else. Hope you can find a cure for it, looks like a nice plant. Is it Crassula "Morgan's Beauty"? Could be "Coralita" as well

Mechanical damage and potentially slight over watering? The depression could be fungal.

Just thinking detective style. You showed us the gorgeous basket of healthy plants. Did you buy/obtain them and brought them home in the basket? Now all the plants that were in the basket (except the Jade) have this "malady". Then there are over 50! plants with the same malady. I'll assume a bit here until you correct me. You have a large collection of Succulents, so a pretty experienced succulent grower. All plants are ok. Then you bring home a basket of Succulents for a group planting. A week after replanting, the malady appeared on some plants in the planter, then on the others (except for the Jade). Within the next few days, over 50 of your entire collection has this malady. There has to be a connection... Same growing conditions causing malady to many plants? eg Oedema. Insect and/or lavae/eggs came in with basket? Something originating from the planter? eg something left from previous plant/s. Anyway if you're interested... could you rewrite the "happenings" correctly and with as much detail as possible. Eg I bought the new planter from bunnings or guy next door gave me the planter when he moved 3 weeks ago. First sign of malady- day/month time I noticed on #of plants in planter. If your not interested, that's cool. Also wondering if you’re into the fast draining gritty mix that rina was talking about. I use it now. Incredible difference in the plants health, not being stuck in unnatural cloggy dirt. BTW What general area in/around Sydney are you in. I spent a lot of time going to Richmond to stay with a family friend during her last years. She died, content, about 2 yrs ago. I would have been visiting about 3 years, several times a year. She was like everyone's favourite Aunty when I was a kid. Sorry that was just why I was interested lol

I don't believe it is oedema. I don't think it is sunburn either - but possibly. At least on first plant. Ppl posted photos of similar damage, and it is likely caused by something chewing on it while still younger. Those 'bites' have scabbed over. As the plant grows, rosette opens up more and damage is more visible. You can see it is sort-of regular. Very young growth is usually most juicy/succulent, and it is often first to be chewed on. One doesn't have to see the bug or pest for it to happen...and just because other succulents were not damaged, it doesn't mean it didn't happen to this one. I actually witnessed this to happen. As Dominyka said, those leaves will eventually grow out, and plant will look better. April If you don't mind here is a suggestion: hope those metal tins have drainage hole(s). If not, they should be drilled or poked in. And if possible, top up the potting mix so the plants are not so deep inside of them. Metal heats up more than terracotta (didn't compare it to plastic); and plants are even 'hotter' if they are deeper inside. And it restricts air circulation too.