Issues with Dust Connecting to All Selected Slack Channels

Folks, adding slack connection to Dust I selected a lot of channels and I see Dust is indeed joining some of them but not all. On Connection Admin I can see channels being listed as available for Company Data and also a Last Update but Dust hasn't even joined them yet. What can I expect from this? its already several hours and I dont see new joins. Will it eventually pick up? Anything I have to do?