It’s not a bug per se, so I don’t find it necessary to post a proper bug report.
The thing is, if you have a number of Object Channels, let’s say Red, Green, and Blue, and you have anything that references these Object Channels, like Radial Force, for instance, or any kind of Trace For Objects, and the array of affected objects is:
Red Green Blue
If you delete Red, the result that I expect would be Default Green Blue
But what actually happens is Green Blue Blue
I understand why it happens: the array uses indices of the Object Channels instead of names, and when one Object Channel gets deleted, all the following are shifted one index up, and it may break things in your project.
However, with meshes that use Object Channels for their collision, everything is fine. If you delete Red, Red becomes World Static, but Green and Blue remain Green and Blue; the selected Object Channel for mesh collision must be saving the name of the Channel, not its index.
So I believe Radial Forces and Traces For Object (and some other stuff that may reference Object Channels in similar ways) should use Channel names instead of indices, just like mesh collision settings.