Play symbol on Vimeo videos sometimes there sometimes not?

Hello SI Team

I think I know what the pattern is and I think it is best if Arlex looks at this who kindly helped me with some mission critical Vimeo issues I had.

https://stackideas.com/forums/vimeo-and-adding-a-video-album-to-easy-social

I have a mysterious play symbol with black semi transparent box appearing sometimes.

As far as I can tell this only happens on embedded VIMEO videos.

Here are three examples:

1)

https://finalbug.net/videos-learn-fcpx-davinci-workflow/categories/14-craft-of-editing

On the VIMEO video

"5 Things Film Editors Literally Do - According To Science"


2)

https://finalbug.net/videos-learn-fcpx-davinci-workflow/categories/23-design-general

On the VIMEO video

"A Brief Lesson on Color Theory"

3)

https://finalbug.net/videos-learn-fcpx-davinci-workflow/categories/11-fcpx-homegrown

On VIMEO videos "FCPX MFX.1.01" through to "FCPX MFX.1.05"

But not for VIMEO videos "FCPX MFX.1.06" to "FCPX MFX.1.15"

kindly advise

Paul