I just sent the email and JSON file to support. Thank you.
To be fair, I'm not at all surprised that Channels is holding onto it's "memory" of these recordings which is specifically why I am requesting a database function more similar to Plex that is dynamic based upon the folder contents. It obviously doesn't work this way currently, but would be nice if it could in the future.
After some discussion with support and testing, you were correct initially. While I assumed Channels was deleting files, it was only deleting placeholders. The curl command does work as expected and will place the "deleted" files in the Channels trash to be auto removed the following day. I can set a cron job on the server to do this daily and I won't have to manually remove from Channels.
I apologize for the mixup.