You have created Supplier and Tax Authority for a particular Business Partner. When you block the status of the Supplier, the status of the Tax Authority and the Business Partner is also getting blocked.
SAP Business ByDesign
The Supplier and Tax Authority are the Roles of the Business Partner and the status is completely dependent on the roles of Business Partner.
This is the general system behavior.
So, if you block the status of the Supplier, it will block the status of the Tax Authority and vice versa. This will also block the status of Business Partner.
In general, if you block a status of one Business Partner Role, all the roles will be blocked.
business parter; business partner role; tax authority; supplier; account , KBA , AP-RC-BCT , Business Config. Tools (SAP Business ByDesign , How To