On the other hand, mine's not broken on my devices that have 8.1
So, it may be difficult to troubleshoot since the issues isn't affecting a large percentage of users. Note I said "percentage" and not "number." If, for example, Roku has 10-million users and 10-thousand are affected, that's 1/10 of 1% affected. Still a large number, but a small percentage. And hard to troubleshoot.
That's not to say "sit back and accept it" but to help understand that if a small percentage (even though a large number) are affected, it may take a lot of time to resolve if the cause isn't known.
That said, if more people would provide info regarding the setups, such as the TV model and device model number, that would help others with access to the same setups to determine what might be happening.
My Ultra (4660) has no problem with my TV, unlike JohnB. So, something else is at play. HDMI cable? TV? Difference software builds? Don't know. Something is wrong and impacting some users. But not all users. That's what makes fixes hard. Not just this one, but all fixes.
Roku Ultra (4660)
Apple TV (5th gen), TiVo
Roku boxes from every generation.
Apple TV (2nd, 3rd, 4th gen)