Approval Rules do not work if there are approvals in the workflow, even if the Approval engine is set as 'Approval rules' on the 'sc_request' table
When there are approvals in the workflow, it still takes the approvals from the workflow. If there are no Approvals in the workflow, Approvals will be created from Approval rules.
As this is the case, Approvals can be managed by approval activities or approval engines, but not both.
1.Workflow on the 'sc_request' table needs to be set as inactive.
2. Approvals activities needs to be removed from the Request workflows
We have a product documentation on "Approval workflow activities and approval engines". This can be accessed from below url