"Resource_already_exists_exception" on OpenSearch Dashboard

OSS Version: OpenSearch Dashboard 2.15

Hello, I got this error while enabling “data_source”
I found these by running querying the default settings: “message”:"[resource_already_exists_exception]: index… and it suggests delete .kibana_2

After I deleted .kibana_2, it appeared to start up.

However, does anybody know why it happened? I got this message a few times… just wanna know more about the root/error message