After changing the default currency of a Money attribute, you create a new instance of the related object in the Modern UX and it still uses the previous currency.
Steps to Reproduce
Expected Results: The Money attribute in the Details flyout shows €10.
Actual Results: The Money attribute in the Details flyout shows $10.
The default currency for the attribute is cached in the session.
This is working as expected. As the default currency is cached in the session, log out and log back in for the new default to be applied in new instances.