Uncaught TypeError: wp.i18n is undefined

I’m using plugins that create custom fields and frontend edit forms. Plugins are from the same author. Am running WP 5.6.

When editing a form containing colorpicker fields, I see the error in the subject line in inspection tools with a reference to /wp-admin/js/color-picker.min.js?ver=5.6:2. I’ve raised the issue with the developer but they say the error content doesn’t point to a problem with their plugin. I’m out of my comfort zone with JS but I’ve gleaned enough to suspect the error could have something to do with internationalization. I’m not using anything that defers loading of JS files. I’ve cleared browser cache with no success. Might the custom field plugin need to add wp-i18n as a dependency?

Is the plugin author right (in that it’s not their problem) or is there something I can do or check to prove the opposite and get the issue sorted? I’d appreciate any assistance – thank you. (apologies if I’ve raised this in the wrong forum)