When coloring a beacon beam with colored glass, the color will be correctly applied only if you place the colored glass directly on top of the beacon. If you place the colored glass a few blocks above the beacon, the beacon beam will act as if there were white glass blocks between that glass block and the beacon.
- Build a beacon
- Place a red glass block on top of it
→ The beacon beam is completely red
- Place another red glass block on top of the first one
- Break the previous red glass block
→ The beacon beam is now pink-ish