When a renewal is processed prior to the expiration date the contract status changes from Active to cancel even though it has valid dates

we have experiencing very strange issue that is When a renewal is processed prior to the expiration date the contract status changes from Active to cancel.

For example: a contract has been issued from January 01st 2014 to June 30th 2018, so, if the customer has apply for renewal on March 01st 2018. from dates July 01st 2018 to June 30th 2022. Now the Prior Contract(which noted as January 01st 2014 to June 30th 2018) goes to the cancel status and the new contract(which noted July 01st 2018 to June 30th 2022) shows to Active status even though the prior contract still has valid dates.

Hope you understand.

Please suggest me what to do.

Thank you so much.