Can't clone, "Invalid reference Id"

Since the update to 9.3 my clone pages do not work

I have products per country, in the page I only have one model, the product model

The country is filled from the original product

If you try to save

If I open the country selector and select the country and save again It returns Invalid reference Id

It seems to be trying to clone the Country__c object…

As odd as this may sound, try switching themes back and forth. I find, strangely enough, that Classic simply doesn’t do cloning on 9.3, but the others do once you switched the themes up.

… tested with the new lightning theme and the modern theme… and it works now…

should I start changing my classic theme pages to other ones to avoid things like this?

Dunno really. I’ve only had the one issue that relates to this.