No experience with the MLB app or a Samsung smart TV, but YouTubeTV has been rolling out changes to the live guide. Someone that is sharing my account has been updated, but I haven't even though we are both using NVIDIA Shield. The web versions are also different. In other words, it can be changed depending on platforms or accounts. Welcome to streaming?
EDIT: when I say sharing my account... YTTV allows 5 people to share your main account.