The Incorrect Variable Matrix is part of the TranslatorHQ comparison reports. These are used to outline products linked to your Retail Express system and your eCommerce store. 

This particular report outlines the products that do not have the same amount of variables in Retail Express and your eCommerce store. These are normally sizes or colours. We have to update the whole product and variations at one time, so, if a size or colour is missing the whole product can not be updated!

This is an example of the matrix report and here you can see it showing different variable numbers. 

So in this example the Manufacturer SKU or Code in Retail Express 7341 has 126 different sizes and colours but there are 127 in the eCommerce system!

So this report tells you what product/Manufacturer Code is incorrect and what stores it doesn't add up to. Products appearing in this report will also appear in Reports 2 and 3 so this is more of a summary of issues that a core report.