H5P presentation - full screen button not consistently appearing

In H5P presentations the full-screen button sometimes appears, sometimes it does not. This happens in the 'environment' and I can't find an explanation for it. There are no settings to enable/disable the full-screen button. I experimented with 2 presentations with the same content in the same environment (browser: Chrome on desktop), please see attached screenshot.

Any explanation, please?

Thanks and regards

Irmgard