mojave error when opening new safari tab

I'm having an issue when using safari and selecting to open a new tab. When I click "open in new tab" it opens in a new tab but also opens in the tab that I was already in. For example, when on youtube homepage I click "open in new tab" on a video which then opens that video in a new tab but also in the tab which I wanted to stay on the homepage. If you have any suggestions on how to fix this that would be great, thanks.