Curious? Have two iPad Pros, 12” and 10.5”. 10.5” on iOS 11.2.5. 12” on iOS v11.3 Beta. Because of old eyes, generally use 12” for tv viewing. This a.m., noticed Channels was listing “wrong” NBC channel, 8 instead of 10. Opened CHANNELS web view on 12” to make sure channel 10 was “hearted”. Nope, wasn’t. 8 was. So, deselected 8, 
️ ed 10. Change didn’t show up in 12” iPad or 10.5 iPad. Closed everything on both iDevices. Followed the same procedure 10.5 (without iOS BETA). Change to channel 10 worked. 10 showed up on CHANNELS App of iPad 10.5 without BETA. Still didn’t show up on 12” iPad with BETA iOS.
FWIW, I think something changed in iOS BETA that you may want to check out.