I have the same issue as the many other posters to this thread, and have little confidence in a fix, given Roku's response so far to an issue clearly affecting many users, starting around the same time, and there has been no resolution.
But since Roku Community Moderators have asked users to provide the following info, below I am posting as if this was a novel issue.
Problem description: About 1 week ago, our Roku TCL Live TV Channel Guide started working incorrectly, as follows:
1. The Live TV Channel Guide defaults to displaying the Live TV Category list, rather than minimizing it and displaying the channels column.
2. Rather than defaulting to the All Channels or most recent category, the Live TV Channel Guide defaults to the "Recents" category.
3. If one navigates within the Live TV Channel Guide to All Channels, that category defaults to the lowest channel (Ch. 2.1 in our case), rather than the most recently used channel. This means that the user must navigate through the whole channel range until locating the desired channel.
4. When the above irregular behavior began, all Favorites appear to have been deleted (though we've since added a few new ones to test that functionality).
Here is the additional moderator-requested info in my case:
•Roku device model, serial number, device ID, and software OS/version (these can all be found in Settings > System > About)
=> MY INFO/RESPONSE: TCL Model #: 43S405 Serial #: YNOOU3663297 (not sure if digits 3&4 are letter "O"s or zeros) Hardware ID: 7101X Device ID: 8L681U663297 Software version: 12.0.0 build 4182-30
•Does this issue occur on a specific channel? If so, what version/build is the channel? (This can be found by selecting the channel on the Home screen and pressing the * button.)
=> MY INFO/RESPONSE: SEE ABOVE PROBLEM DESCRIPTION. Also note: The issue occurs regardless of what channel is selected.
•Tracker ID when this issue occurs (when you see this issue occur, press the Home button 5 times, followed by the Back button 5 times, and provide us with this ID).
=> MY PROBLEM TRACKER ID: 97-365-876
•What are the steps to reproduce the issue you are seeing?
=> SEE ABOVE PROBLEM DESCRIPTION. SINCE BEGINNING, THE ISSUE HAS BEEN CHRONIC DEFAULT BEHAVIOR within the Live TV Channel Guide.