Joseph Rézeau

Thanks for the screenshots. It's not easy to understand why you are having this problem. Could be one of your plugins or theme settings interfering with H5P. I don't think that the problem only arose because you updated to Moodle 4.3. H5P works fine on my Moodle 4.3 sites.

The only weird thing I notice on your Accordion edit screenshot is that the font does not look what it should be. Compare with my screenshot: 

Could you provide a) screenshots of a couple of H5P contents (other than Course Presentation), e.g. Multiple Choice, Accordion showing the problem? And also a screenshot of your browser console showing error messages?
I don"t think the server version is relevant.

Thanks for your reply with the attached image. I cannot reproduce your problem on my Moodle site running version 4.3.
Your screenshots seem to be showing a Course Presentation H5P content. Can you confirm that your problem only happens with that type of H5P content, or on other types also?

Hello,
I suppose you are using the h5pactivity integrated in Moodle core (blue icon + Content bank)?
Which Moodle theme are you using? If you are not using the Boost theme (default) try it to see if it solves your problem.
Which H5P contents are you having problems with their editor? all of them or some of them?
You have not attached your screenshot image!

Hi
"we are having the same issues ..." is too vague for us to help you out. Please provide a maximum of information, including screenshots, Moodle version, H5P question types, etc.