Do you have a SlingTV shortcut button on your remote? It may be stuck/sticky or even faulty. On one of remotes with Sling button, sometimes using the navigating arrow buttons will somehow inadvertedly trigger Sling to start installing. I simply uninstall it when it attempts it. Maybe try giving the remote a little cleaning.
Others have reported that certain screensavers (those with embedded ads) will also affect channels automatically installing. Try using default Roku screensaver if your issue.
As to your other question, a little unclear what you needed re: the cable provider app.
Roku Community Streaming Expert
Just another Roku user... I am not a Roku employee.
Insignia RokuTV, Ultra 4660x, Premiere+ 3921, Express 4k+ 3941