Bernard
Were they easy to scrape off?
Doesn't look like scale to me - scale is round or oval, little bumped-up in the middle. When scraped/wiped off, usually there is reddish liquid (blooood!) - sign that it is living thing (unless they are dead - if so, they usually look 'papery' to me). They multiply, but maybe not so fast? (you said many appeared overnight).
Hope you didn't injured the leaves.
Not sure what else it could be.
Are you sure it is e. nodulosa? Photos I have seen (and one I have) shows always red striping (not all green leaves with just red edge). Here is tiny clipping I took off the main stem just few days ago, it is just about 1" across.
Of course, I could be wrong as often before...

Rina

They do require some force to remove, but upon so, there were no signs of reddish liquid, just exposed green flesh of the leaves. I stopped after trying a few times last night, in hopes it will heal over and be gone. However, the spots replace the exposed parts again this morning. I have no idea either, hopefully these spots are not detrimental to the plant's health, I'm starting to see one spot each on each leaf now.

I am very certain its a E. nodulosa - it was the pup that I had removed whenI first got the mother plant for my terranium.

My nodulosa is definitely losing its markings, I'm alittle worried because I don't know how to diagnose this problem and help it.

Any thoughts or guesses?

Thanks, B

Now I can see faint marking on large leave. I don't know what to suggest but sun? But I had mine indoors for so many months, with some supplemental fluoro lights, by north window and it didn't loose the stripe. Maybe just because your babies grew from the leaves - I clipped mine from the mother stalk. Time will tell...as long as they are healthy, eventually they will show their true colors.

At this point, maybe just watch the spots. Not sure what it could be, perhaps oedema? I see similar spots sometimes on jades (not too often), and the plants are very healthy. Looks almost like corking on cacti.
Maybe you should get really good magnifying glass to look at things.
Rina

ps: I just took couple of photos, there are few similar spots on these 2 jades (I don't worry about them-they are not getting any bigger and leaves are not dying):

All my seedlings gets almost 8 hours of full sun now, with the exception of this week being rather cloudy. Interesting, I don't even know what oedema means until I searched it; never knew it could affect succulents.

I should probably treat and water this guy like an adult plant now, I tend to water more for my seedlings. Perhaps its taking too much water than its leaves can handle.

Thanks for the diagnosis!

B

"They do require some force to remove, but upon so, there were no signs of reddish liquid, just exposed green flesh of the leaves. I stopped after trying a few times last night, in hopes it will heal over and be gone. However, the spots replace the exposed parts again this morning"

Well it looks like mechanical damage and it acts like mechanical damage, so that's my guess....

k8 - you can see from the pictures before and after, they started with leaves barely with an inch long (no damage whatsoever), but as they grew bigger these spots and scars developed. I've always grown it with my tray of other seedlings, so it definitely gets more care and attention.

My next guess is probably a bad reaction to too strong sunlight behind the windows, hence leaving scars. What's strange is that my other baby plants are doing fine.. except for a couple of variegated coloring on some leaves.

Thanks Rina - I'm probably worrying too much, but I'll definitely keep a close eye on them for now.

Bernard
I don't think sun will cause these kind of spots/scars, it would be larger, irregular sunburned spots if that was the case. It could have been minor mechanical damage when handling and just scarred over - just as k8 suggested.
Rina