Hello @nancylat , welcome to the QuickSight community!
This is something that has happened in other regions or there have been bugs in the geo-spatial mapping.
I would recommend filing an AWS support ticket. Here are the steps to open a support case. If your company has someone who manages your AWS account, you might not have direct access to AWS Support and will need to raise an internal ticket to your IT team or whomever manages your AWS account. They should be able to open an AWS Support case on your behalf.