If it’s not on uservoice theres no “paperwork” for it. Since reddit is just reddit. You don’t know if that staff member that replied, is still staff or if they even entered it into their “feature tracker/ideas board/whatever”
There is no “fix” because it’s not “broken”.
The embed will embed a channel as described by the channel you tell it to display.
if you want it to be “host aware” you have to write your own code to detect the host and change the displayed channel in your embed.
At time of writing the embed does have a “show another channel if in target channel is hosting” flag.