I'm not buying this, there's just nothing that supports the claim, not even in which country this happened.
A proper leak should include said memo...
We do not know for certain if a "national financial institute" actually sent a memo, but there is no doubt that a number of banks in several countries are suspending accounts for Bitcoin related activities,
according to reports on this forum.That happens since ever, I remember there was a website dedicated to that like two years ago, badbanks.com or something like that, to be fair banks do this to all clients they thing pose a threat to compliance, not just bitcoin related.
The claims made are much higher and it may actually be illegal in some countries to do such thing as we have bank confidentiality that can only be lifted in very specific conditions.