ELI5 Glossy Reflection

[Crazy Homeless Guy]

Explain like I am 5 glossy reflection... 

I recently added a bit of glossiness to my reflection and it made the reflection not behave predictably.  It made the reflection appear as though there was refraction issue with the glass.  After digging around a bit I found out that enabling caustic reflection or enabling this glass option fixes the issue glossy reflection issue.  Can someone shed light on this?  Is this a bug or a feature?  Because it feels like a bug to me.

[pokoy]

Is this in max or c4d?

[Crazy Homeless Guy]

Max + Corona 1.7

[pokoy]

There was a similar issue with the c4d version if I'm not mistaken. Best would be to provide a simple repro scene, this should get fixed.

[maru]

This is probably an instance of light transport issue with hybrid glass: https://coronarenderer.freshdesk.com/support/solutions/articles/5000516180-known-bugs-and-limitations
I will look into this...

[pokoy]

I came across this in some scenes and realized only after reading this thread, I had glass panes with 0,99 reflection glossiness and they reflected something that was impossible to reflect from where they were. Going back to 1,0 glossiness on all assets now. I don't remember happening this in earlier versions though, but not sure.

[maru]

Can I have a simple scene where this can be reproduced? I had trouble creating my own.
The workaround would be probably to use rayswitch mtl with:
-glass with caustics enabled plugged into direct visibility
-glass with caustics disabled plugged into everything else