Loans create new money. I never denied that.
If the money JP Morgan loaned California is brand new money, then JP Morgan's reserves are unaffected if someone cashes a check on California's 1.5 billion account.
The reserves are unchanged. I never denied that.
Your original claim sounded as if JP Morgan makes a loan and gets to keep the original $1.5 billion in deposits. That they make loans without money leaving the bank. That they can make loans, without any deposits. That's not the case.
Every loan must be funded.