What streaming device are you using? Some ROKU devices had a choppy video on the ESPN App. which started sometime on or before the LSU series, but ROKU investigated the issue, and that has been cleared up. I had the same thing initially, that the commercial ads were fine and the live ESPN App feeds were choppy and unwatchable. I sent info to ROKU on what I experienced and what I had done, and they asked additional information from me, and then they emailed and told me that they escalated the case to their engineering group, and shortly after that my ROKU Stick worked fine but my ROKU Ultra still was choppy on the ESPN App.
I think I finally discovered why my ROKU Ultra was still having video issues on the ESPN App. My TV is not 4K, and apparently it could not process the high bit rate that ROKU wanted it too on certain video material on the App, so it would apparently hesitate and then the video would be choppy. I changed the bit rate to a lower number and it works and I still get the 1080P Full HDTV video The Roku Stick works fine after ROKU solved their video issue. It was a ROKU issue.
I initially contacted ROKU then ESPN and then ATT UVerse to check my internet connection as ESPN had said that was my issue, which was proven to be wrong. Then I contacted ROKU again and was in contact with them off and on for a few weeks prior to the issue being resolved.