Mobile: Opacity is staying at 0 on every other element

[mattwillmott]

I have the zoom working perfectly on a Shopify store with the product image and also thumbnails.

On desktop it all works fine for every image. The thumbnails switch to the main image when clicked, and the zoom works on the main larger image even if it's been changed to one of the thumbnails.

However on mobile the zoom effect only works on every other image. I've checked in Browserstack and it appears that everything works as expected apart from the opacity property, which stays at 0 for every other image but works for the ones in between.

And to top it all off, it's not always the same images with the problem. Sometimes it's the 1st, 3rd, and 5th thumbnails that once swapped in won't zoom, and sometimes is the 2nd, 4th, and 6th. I've just figured out that it's every other image from whichever thumbnail I click after the page loads.

At a bit of a loss as to what's causing opacity to not transition to 1 on alternate images, so any help would be hugely appreciated.

[ed-codes]

Having the same issue, also on a Shopify store.