Hi, @Hawgowar
We're glad to have you hear in the Roku Community.
We understand the concern you've brought to our attention, and we'd like to gather more information. Are these videos accessed through the Roku Media Player? Also, could you please provide an image referring to the "black thumbnail box"? Further, what specific Roku device you are having issues with?
With more details, we'll be able to have a better clarification at the issue and assist further.
Best wishes,
Kash
Takashi O.
Roku Community Moderator