Each time i click on a new video, a new Share button appears about customtube

This also happens on the 2016 theme as well

[lightbeam24]

I have only tested this on the 2012 layout, but im guessing that its because only the video and the link changes, so it adds a new share button because usually those would go away.

I've had this happen a couple times (though not to this extent). Stuff like this is why I've started testing a major rework of the watch page for all layouts. If it goes well, this rework will have completely replaced watch metadata HTML, so the layout won't break anymore. That said, this update may take a while to come out, since it involves reworking a substantial portion of the extension's code.

[lightbeam24]

This also happens on the 2016 theme as well

This is actually a separate issue that should be easier to fix.

I bet a YouTube update caused the glitch

So until this is fixed I disabled the extension on my browser.