Video Thumbnail Issues

Hello

I have noticed that when using video files in the gallery, the thumbnail does not appear in Safari and Opera browsers (on Mac). Just showing the transparent area where the video should be. Once clicked and in Lighbox, there is no preview, but when click the play icon, the video works fine.

It works in Chrome, Edge and Firefox.

I tried uploading separate feature images to media, but with no success. Can you check/advice on this?

Thanks

Bojan