When I deploy external object through Metadata API, it dosn't add any custom fields so I can't use the fields.

Details:
version: 39.0
1. On "Setup page"  > External Objects > Custom Fields & Relationships
    I can see all custom fields, which is good.
2. On "workbench.developerforce.com" > Standard & Custom Objects
    I can't see any custom fields here! Is it a bug?

When I delete the external object and add again by "Validate and Sync" through "Setup page", I can see all custom fields on "workbench.developerforce.com".
It happens only when I use metadata API.
It means if I want to remove/add any fields/external objects, I need to delete all related classes/objects first and sync the external object on GUI...

Does anyone have same issue or workaround?
Thanks

When I deploy external object through Metadata API, it dosn't add any custom fields so I can't use the fields.

Details:
version: 39.0
1. On "Setup page"  > External Objects > Custom Fields & Relationships
    I can see all custom fields, which is good.
2. On "workbench.developerforce.com" > Standard & Custom Objects
    I can't see any custom fields here! Is it a bug?

When I delete the external object and add again by "Validate and Sync" through "Setup page", I can see all custom fields on "workbench.developerforce.com".
It happens only when I use metadata API.
It means if I want to remove/add any fields/external objects, I need to delete all related classes/objects first and sync the external object on GUI...

Does anyone have same issue or workaround?
Thanks