I just setup our new Roku TV and at times the Live TV app displays an animated screen with the message
"Don't go anywhere. We will be right back'
It is really annoying
Those fillers represent commercial breaks the content owner has inserted where the systems that carry the program can insert advertising. When nobody has purchased the ad time you see the filler.
I much prefer those unobtrusive ad holders (usually with some elevator music) as, compared to the loud, annoying typical ad/commercial breaks.
Totally agree with you on that