Does the issue only occur on a specific channel or across other channels installed on your Roku device?
If you haven't tried it yet, you can remove the affected channel and then re-install it. To ensure the process is successful, restart your device before adding the channel back in. We would recommend doing this from the Settings menu by navigating to Settings > System > Power (If you do not see a Power submenu, skip to the next step.) > System restart.
As @renojim has mentioned, if you are experiencing playback issues with the HDHomeRun channel, you'll want to contact the channel provider support directly to inquire further. Many channels on Roku are developed and maintained by the channel provider themselves.