I notice when I want to play recently embedded YouTube videos it takes two clicks to before the video will play. Some of the older YouTube links will play with a single click.
I think the difference is related to the way the forum software adds the video tags.
The video below was added by pasting this text without the spaces or quotes. "[v ideo=y outube;f520FM9Z9is]h ttps://w ww.youtube.com/watch?v=f520FM9Z9is[/v ideo]"
Edit: The link didn't work. I pasted the text from this forum post
but the video wasn't embedded properly here.
The video below was added by pasting the following text (again without the quotes or spaces). "h ttps://w ww.youtube.com/w atch?v=25Gt31mT7g8"
I think the later example looks better on the screen but I prefer the first version (as seen in the other thread) since it only requires one click to play the video.