Could an unstable internet connection be the root cause of the `err_pb_1413 bff` error on a Hisense TV?

Yes, an unstable or weak internet connection is a very common cause for the `err_pb_1413 bff` error. If the TV cannot maintain a consistent connection to the content servers, or if the bandwidth is insufficient to stream, it will fail to load content and display this error. Check your Wi-Fi signal strength in the TV's network settings, try moving the router closer to the TV, or connect via an Ethernet cable if possible to rule out Wi-Fi instability.