Original topic here
https://forum.corona-renderer.com/ How to process reflection + shadow
if you open the scene it has black color in environment and one light source, if you lower glossiness in shadowcatcher, the reflection of object disappear in alpha channel, and it will appear again if you change color in environment or turn off light source.
another bug if you set intensity to light source 0 it start to reflects in alpha
video demonstration with scene files are attached
ShadowCatcherBug.flv (2.85 MB)
reflection test.7z (58.4 KB)