When you look through stained glass, no particles are shown when looking through the stained glass, but when you look through normal glass, the particles can be seen through it. I have tested this with rain, noteblock note particles, and torch smoke particles on both 1.16.1 and 1.16.3. The results are similar. The attachment is a picture that shows the torch and rain particles not showing up on the black stained glass, but they show up on the normal glass. The screenshot was taken on 1.16.1. Hope this was useful.