In situations like these, we suggest trying to remove the channel and then re-adding it to see if it resolves the buffering issue. 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.
If the issue persists, we recommend reaching out to the channel partner for additional support. Channels on Roku are created and maintained by each channel publisher. In this case, you'll want to reach out to Spectrum support directly to share your feedback.