Just to let you know I managed give this a go on my old iPhone 6s with the latest 12.1 iOS and they same issue happened.
It's odd as the app has clearly been updated recently as its got a new layout which is much better I have to say, works like a dream on my Samsung S8 work phone.
Be interesting to know if the TV App product manager is seeing the same as it could be something todo with my talktalk account or maybe the apple account on the phones.
Just a thought, slim one I know. I have just had another look at the app myself, have you tried going into the Filter and selecting Clear All? Very frustrated that I can't test more deeply, but unfortunately I do not subscribe to any Boost channels at the moment.
Our product manager has been in touch to request I pass over all your details so they can have a good look at your account and all other settings, so I've given them the info requested.
I've emailed out TV Product teams on this as I've yet to receive an update.
If I don't hear back by the end of today then I'll escalate this through my senior managers here to chase this for me.
Our TV teams have been fully testing and are unable to replicate this issue.
They have also had a look at your account for any obvious issues, and nothing looks out of place.
They have asked if you know anyone in the family with an android device who can install the app and test with your account credentials etc to see if this is affecting the IOS version or the account specifically.
I did already mention it’s working fine on my work android phone. I tried logging out and back in again and when I use my email address and password opposed to using quick sign in on my home WiFi it states “TalkTalk tv isn’t registered on this account”
But quick sign in allows me to log in, very strange.