Virtual Categories Root select : default/root category not pre-selected anymore

[rbayet]

In M2 2.2.8 and 2.3.1, when creating a new virtual category, the "Virtual Category Root" select does not pre-select anymore the store default/root category.
In 2.2.8, the select displays/has pre-selected a "Select..." option.
In 2.3.1, the select displays/has pre-selected a "Entity with ID: 0 doesn't exist" option.

Preconditions

Magento Version : 2.2.8 and 2.3.1 (CE and EE)

ElasticSuite Version : 2.6.8 / 2.6.x-dev and 2.7.6 / 2.7x-dev

Environment : Developer and Production mode

Third party modules : N/A

Steps to reproduce

1. In admin, create a new sub-category under an existing category, save it
2. In "Products in Category", switch "Virtual Category" to "Yes"

Expected result

1. The "Virtual Category Root" select which appears should have pre-selected the current store default/root category option
   

Actual result

1. In 2.2.8, a "select" option is pre-selected instead, the actual default/root category option being below
   

2. In 2.3.1, a "Entity with ID: 0 doesn't exist" option is pre-selected, the actual default/root category option being below
   

[rbayet]

I cannot find the related issue on magento2 tracker so I cannot say it's written in stone and true for every category attribute, but it seems now that upon the category creation, the category attribute virtual_category_root is written to the DB with its configured defaut value (0), which is ignored by the DataProvider plugin.