My account was randomly locked once too, with no warning or explanation. I went out to eat, tried to pay, and my card was declined. Chase said that there was some system whereby the treasury can just flag/lock accounts, and that they didn’t know the reason. I still don’t understand what they mean, but that’s what they said and that’s all they would say.

I was never involved in any shady business, the only money went in from payroll at a reputable company, and I only ever made normal purchases.

I also learned that you have no right to any money in your bank account, the bank doesn’t owe you an explanation for denying access, nothing. They also don’t owe you any damages from denying access. I had a rent check bounce because this. It’s pretty crazy. After this experience, I learned it’s increasingly common.

Do not ever keep money in a single account, you may be denied access without reason at any time.

Luckily for me, after two weeks, they “unlocked” it. Again, with no notification or explanation.