unexpected behaviour of custom hold in AP - R12.1.3

Hi,

We have a custom payment hold xxsl bank account, with description as Bank Account does not match with that mentioned on the physical invoice. We have defined it in the hold and releases window in AP setups. This hold is getting automatically assigned to the invoices coming from third party systems via interface. We are unable to understand the logic howw this hold is getting applied on itself. We have checked the custom validation package, but could not find anything. Could anyone please suggest where can we find the possible conditions which might be triggering this hold. EBS Version in