That's a lot of room temperature variance. Powdery mildew?

Looks like something is taking an occasional nibble while the leaves are still small, bunched together, causing a deformity at the same spot in each affected leaf. I'm not sure what does that, I see it on my plants occasionally but have assumed it happened while they were outside, something that took a few bites and flew away.

Otherwise, from what I can see in this pic, your plant is amazingly beautiful and happy-looking! Love those perky, colorful stripes!

Banding like that on the foliage of dracaena is most often associated with chill injury. Any chance the plant got too cold this past winter? Is it sited where it will get cold drafts?

Al

I agree with purpleinopp!
Looks like something has damaged the leaves while they were still forming. Maybe even a chill, as Al suggests.
If you had mealy bugs before, maybe that's the reason?
It can be hard to pin these things down but overall your plant looks really nice.

That happened to mine when i picked it up and it hit the ceiling, bend the new growth tip. All the leaves that came off of it for a time had that bruising to the leaves. Still waiting on the darn thing to grow taller so those leaves will naturally fall off!

I'll link you to a commercial production guide for dracaenas. You might want to read the entire guide, but at least scroll down to where it lists physiological problems under chill injury.

Al

Here is a link that might be useful: Dracaena info