I'm not convinced that what you have is trigona. It doesn't have the same markings or growth habit. But with so many different cultivars out there, tracking down an id on yours might prove a challenge. I'm no Euphorbia expert, but I'll bet someone on here knows exactly what you have. You might try posting this in the Houseplant forum as well. I think you might get more responses that way, since Euphorbia isn't technically a cactus anyway. And the spots really look like sunburn to me, especially since you say that it was recently moved outside to full sun for a while. However, like I said, I'm no expert. I think your best bet is to repost this in the Houseplant forum. Good luck!

This is definitely over watering. If I was you I would put in another pot with a few drain holes or one at least and inch big. I use cactus soil, perlite and fir bark chips which I get at the pet store and mix in quit a bit of bark and go heavy on the perlite. The plant like moist soil but likes to dry out some in between watering indoors. Outdoors in the heat it would probably need more but it's better to under water than to over water. You can take off the damaged leaves a couple at a time so you don't shock your plant and it will get new leaves. Mine I water in my plant room under lights in a south facing window with a white curtain once every 7-10 days with luke warm water not cold. I don't spritz them with water either. That promotes fungus and rot. They need a lot of bright light no direct sun to keep the variegation. You can also invest in a cheap moisture meter from Lowe's or Home Depot for under 10.00. I don't water until it goes into the dry and stick it down by the roots. Try it in a 6 or 8 inch pot if the one it's in is a 6 inch. I use regular tap water and once a month I use 1/2 what the ingredients says Dyna Gro Foliage Pro fertilizer.

So this is normal? Even the browning at the base? Cuz I'm terrified of scale and after going through it in really bad about picking them off and a couple cactus I've don't that too have rotted cuz it left a hole that turned black in assuming from some type of fungus and then of course dies. I'm trying DE on one right now that I've been trying to save for months now. Anyway hard to tell if I'm being paranoid or what's normal cactus now.

many plants are .. its not that big a deal .. once you have the knowledge to deal with it ... and now you do ... dont put it in the babys crib.. dont put it in/or near the litter box ... and the pointy things ought to keep the dog away ... and dont try frying some up for guests.. and you ought to be all set .. lol ... ken