> what specific reason they have for triggering KYC/AML

As far as I understand, they're often not allowed to disclose that. E.g.,

https://www.bitsaboutmoney.com/archive/seeing-like-a-bank/

> In the specific case of “Why did the bank close my account, seemingly for no reason? Why will no one tell me anything about this? Why will no one take responsibility?”, the answer is frequently that the bank is following the law. As we’ve discussed previously, banks will frequently make the “independent” “commercial decision” to “exit the relationship” with a particular customer after that customer has had multiple Suspicious Activity Reports filed. SARs can (and sometimes must!) be filed for innocuous reasons and do not necessarily imply any sort of wrongdoing.

> SARs are secret, by regulation. See 12 CFR § 21.11(k)(1) from the Office of Comptroller of the Currency...

The fact they may not be able to in one circumstance doesn't prove that they're merely following the BSA.

It's obvious when someone gets their money frozen for a month only to just have to perform a KYC check that even if the KYC check was legitimate, and these kinds of results are common over years, the delay was a result of a business decision that increased their float.

I think you're conflating the requirements with the BSA with how executives are using it in a hostile way against customers. They can make the deliberate decision to slow down KYC/AML officers and checks after a trigger, while putting them on a hair trigger, while citing secrecy under the BSA. That is the regulatory nonsense under which they are dressing up a business, non-regulatory decision. It's there to provide plausible deniability.

The compliance officer in this case is plausibly just following the law but in reality they're just running cover for increasing the float -- maybe even unwittingly.