Update:
Box and search are now working exactly as it should. ODN-keybpard advanced B-button search now finds all content, just like it did before October 2018.
Research, with help from the escalation teem, and guide engineers, identified the problem. ODN advanced keyboard search (b-button) contains a filter, that when activated, forces a lot of channels and search content to not be found by the keyboard. The tech team removed the filter and now the search works great!
I want to thank the guide team engineers and developers for seemingly solving this issue, and hope that this issue stays resolved for any others affected by it. Thanks all!
Satch