It is the customer's responsibility to approve or reject bugs, and the review time frame will vary by project and customer. There are some customers who consistently review reports as they trickle in. For example, the test cycle may still be active, but the customer is already approving or rejecting bugs as they are being reported. On the other hand, there are also customers who wait until the test cycle is complete before reviewing the reported bugs.
As a general rule of thumb, please allow 35 days after the test cycle locks before sending a request about why your report has not been reviewed yet. You may request this information by contacting the Tester Support.