Javascript error ecomm_prodid.push is not a function

The site is updated to the latest versions of all plugins and all caches have been cleared.

The Tag Manager plugin is generating the following error, which is then stopping other code on the site from completing.

TypeError: dataLayer[i].ecomm_prodid.push is not a function
https://bootandsaw.co.uk/product-category/surfboard-racks/surfboard-racks/
Line 76

As far as I can tell, I have followed the relevant updates from your new post regarding Tag Manager triggers and tags.

https://www.ads-software.com/plugins/duracelltomi-google-tag-manager/