Lightbox Option

Hello. I have noticed an issue pop-up recently. My product thumbnail and gallery images are not opening up in Lightbox. I went into settings to verify I had that feature turned on (checked) only to find that the option is not there. Looked under Woocommerce->Settings>General and Product->General, Product->Display.

I also notice that inspecting the code on the product pages the <a href> isn’t even calling the lightbox.

Seemed to work fine in the past with my current theme (custom). Could it be a conflict with another Woocommerce plugin? Or do I need another plugin installed?

Thanks for your help.