Steam achievements behaving weird again?

I started NGS at launch, and got to 20 long ago, at least 2 weeks ago. In fact I have 2 level 20 classes (Fo + Te) already. But yesterday when I finished testing out something using a non-20 main class and a Lv.20 subclass, and swapped my main class back to my Lv.20 Force, Steam gave me the "Brilliant Growth" achievement, which says:

[NGS] Proof of reaching Level 20 with any class in PSO2:NGS. ARKS defenders, reach for the stars!

Shouldn't I have got this when my first NGS class reached 20 like 2-3 weeks ago?

Anyone also have the same problem, or anyone running around on a Lv.20 class yet still doesn't have this achievement?

The way the Steam achievements work is you have to switch to the class that met the conditions, it did the same thing on the PSO2 side, it may seem buggy, but I think there is no way to do a check on level up, so the class switch was the work-a-round.

Ah, no wonder. Thanks.