R12.1.3 - how to confirm which Cross Validation Rule is firing

Hi,

We are using R12.1.3.

In iExpenses, when a user goes to raise an Expense Claim, they see this error at the top of the page:

I know this is triggered by a Cross Validation Rule. However - there are 50 Rules whose Error Message value = "This Cost Centre cannot be used with this Division".

For example - here is one:

I have tried many things to try and find out exactly which Rule is firing on the iExpenses page, but I am now out of ideas.

This is what I have tried so far:

1. FND Debug

I enabled FND Debug while the user recreated the error.