[Pugin: NextGen Gallery] Thumbnails not linking to images

Hi all,
I am having a very strange problem. I have tried various methods and also resetting settings but nothing worked. So please help me here.
The problem is that in each gallery on my website the individual images are fine. But when a gallery is opened. The thumbnails don’t take you to the image rather the thumbnail itself opens in light box.

Here is the example: This is gallery explore:
https://iom-group.com/explore/

Now the first image has link:
https://iom-group.com/epic/

But when you click the first image in the gallery the thumbnail opens.

Please help.
Thanks,
Ahmar.