I think the issue is that you cannot withdraw more than you have on-hand. So if you have 100g on you, I don’t think you can withdraw 101g from your bank. Similarly, if you have 10,000g on you, I don’t think you can withdraw more than that amount.
Hoping it gets fixed in maintenance on Tuesday, but it feels as though this is just the source (the bank) being mistaken for the destination (your on-hand gold).