Maybe it’s made to prevent opening links in new tabs when just selecting some text to quote our copy?
When the code you found is deactivated and when you have the “Open all external links in a new tab” option checked,
Could you try to select (mouse down, drag, mouse up) some text that includes links to see if it does not open any of them?
Try with a selection that surrounds links and also try with a selection that ends in the middle of a link, maybe.
The selection should always just select, not open links.