This termination did not happen instantly.

The account was brought back to normal well before the termination of all of our accounts.

I also expected them to have automatic triggers, but at the time they did not.

OP confirmed that his (allegedly human) contacts at Chase were aware of the closure, and chose not to comment.

I would generally also suggest incompetence above malice, but above fact makes that very hard.

It would be a federal crime to mention the words "money laundering," let alone specific tells, to the owner of an account suspected of money laundering. Chase policy probably applies this gag rule to any account being closed by Chase rather than splitting hairs about AML vs. other reasons.

I understand the laws behind that, but personally still think there is a large gap between "we legally can't disclose the reason" and "we are telling every employee to just shut up and say nothing".

I would expect a reasonable middle ground of letting employees say "I'm sorry, but it's corporate policy and I can't disclose more information."