Specifically, the first point in the joint letter states "Surveillance of the global financially system is the responsibility of the IMF". That appears to be inconsistent with the first bullet point immediately below, drawn from the April 2009 G20 communique. 12  BIS Review 107/2009  promote financial stability and "a stronger institutional basis and enhanced capacity as the financial stability board (FSB)."
The fact that a digital euro would be very liquid may lead to foreign investors using it disproportionately and rebalancing much more forcefully into or away from it in response to shocks. Indeed, recent research suggests that, in the presence of a CBDC, shocks could result in greater exchange rate fluctuations and have a stronger effect on foreign financial conditions.