That is pretty bad, it sounds like a criminal investigation should start immediately.
But it is like a smoke alarm going off. It doesn’t mean there is a fire but there could be.
This company is so big that it should have a mature infrastructure for this type of thing. It is quite strange and thus suspicious that it is running its business is a haphazard way that it can not be effectively audited.
Let's just remember that most bureaucracy exists so that only those who persevere can make it to the other side. And even then if you bother the wrong people there's more bureaucracy to harass you with.
Financial oversight groups should start an investigation but it probably shouldn’t be called criminal at this point. Just an oversight issue where they demand more info.
Enforcement bodies start investigation for any reason and none, (see all the stuff FBI did during civil rights movement for example ) at best legal framework used is probable cause
But imagine if a person cannot explain to tax agency some large sums of money flows.