I am not sure what is the best way for AML checking, but we have often seen that some exchanger keeps the funds because their checker "recognized" a high-risk score and marked the coins as dirty. When it is necessary to present the method of analysis, the service refers to the preservation of privacy and the protection of "analytics tools" in terms of future prevention. It mostly ends with keeping the user's coins, without much explanation.
Protecting privacy and prevention, act here only as an excuse for confiscation of funds. Such a system can be applied to any transaction. It acts as a legitimate justification for stealing the user's funds.
Indeed, their AML service might not provide information based on the decision to freeze incoming cryptocurrency funds.
From the user's perspective, a request for data seems like the most logical action. However, such information cannot always be provided directly to the user for various reasons. Nevertheless, the monitoring administration is always committed to fostering a constructive and mutually beneficial dialogue that can lead to mutual consensus. That's why we recommend our users also inform us of any AML incidents for prompt intervention.
P.S. The AML check provided on the monitoring site aims to mitigate the negative consequences of such incidents, allowing users to perform checks BEFORE executing the actual exchange.