Hi Windzor89,
Thanks for your valuable feedback and sharing updates with us and I really appreciate your effort and your precious time doing.
And I appreciate your kind words.
Yes, you are correct, however if I just place a mouse (hovering on the webpart) and the problem goes away.
We have tested it again on our side, and we embedded also video in Embed webpart and we found we can reproduce the same situation as yours, as shown below:
Given this situation, we assume that the developer team used such code to format webpart in SharePoint Online, and we do understand the inconvenience caused and apologize for it. So, to address your concern about the situation, I request you, please send/provided feedback to related Microsoft development team via Microsoft SharePoint online feedback portal, so that they can get notice about it, and we are sure it will speed up this process. Your advice is very important to us.
At the same time, we assume this can be changed via using code format, if you want to learn more about how to use code to change webpart format, we’d suggest you go to Microsoft Q & A forum – SharePoint Development, which is specific channel to handle such situation. And engineers in those forum are very proficient in the knowledge of these codes.
Your understanding and patience will be highly appreciated. I hope that you are keeping safe and well!
Sincerely,
Waqas Muhammad