Bot is not showing up in Teams channel call

The issue is not specifically related to the API or bot's implementation. I have developed a bot that is properly configured and serves the purpose that it is built for once it joins a call. Till a couple of weeks ago, bot was working fine and user could add it in any channel call in a team (where bot is installed) by searching for it in 'participants' search box, the bot would show up and upon selecting, bot used to join the call and do its stuff. For unknown reasons, bot has just stopped showing up when searching for it in searchbox:

The bot works perfectly on 1:1 call. I have checked bot's configurations in Teams app studio, those seems to be ok, as bot supports joining group calls:

Is there anything that could be missing or I can look into to resolve this particular issue.

Expected behavior
For unknown reasons, bot has just stopped showing up when searching for it in search box as shown in the snapshot above. the bot should show up when user searches for it.

Additional context
Just for additional information, below are the API permissions that are granted:

The issue names no repository files, tests, or entry points; start by reviewing the Teams app configuration and listed API permissions, then compare channel-call behavior with the working 1:1 call. Done means the bot appears in the participant search for a team channel call and can join it while the existing 1:1 behavior remains intact.