Using Odata Service, you have created a Lead with 'Use existing Account/Individual Customer' set to 'No'. But still system created an Account/Individual Customer but you are not able to locate the Account/Individual Customer in any of the available workcenters
SAP Cloud for Customer
When you create a Lead with 'Use existing Account/Individual Customer' set to 'No' the Lead still has to store the name, address and communication data you enter somewhere. To do so the Lead creates an instance of the BO Customer. This instance is only technically a Customer, though, while semantically it is merely an extension of the Lead instance. You can recognize these kinds of customers by the fact that they have life cycle status 'In Preparation'.
Since this Customer is semantically just a storage space for that particular Lead it will intentionally not be shown in any regular customer screens.
Later on with the action 'Convert to Account' or 'Convert to Individual Customer' that customer can be converted into a 'real' customer.
Individual Customer in the tenant is just such a Marketing Lead Customer.
If the action 'Convert to Account' or 'Convert to Individual Customer' is disabled in lead, you can enable it using Lead Fine tuning activity -> Maintain Status
Note: Only way to access these Account/Individual Customer is through Enterprise Search where you can search the Account/Individual Customer ID
Account/Individual Customer, lead, in preparation, Use existing Account/Individual Customer , KBA , LOD-LE-BP-BP , Business Partner , Problem