YouTube links in WhatsApp opening in Safari (iOS 10)

[.:.Gio.:.]

Hi everyone,
I'm having this problem: WhatsApp doesn't open my YouTube links in the YouTube App anymore but it opens them in Safari instead.
The last time I opened a link without having this issue, I had as usual the “back to WhatsApp” icon at the top left of the screen but also a “youtube.to” at the top right of the screen; I clicked that and the video I was watching in the YouTube App opened in Safari, so I'm wondering if that may have been the cause of the changing behaviour of my WhatsApp with YouTube links.
Someone can help me fixing that, please?

 

[KALLT]

iOS remembers when you switch to the website once. In Safari, you have to drag down on the opened website to reveal the ‘Open’ button. After that, it reverts.

 

[.:.Gio.:.]

Thanks, KALLT, but drag down what? I didn't get it