Hi Sharan,
we have already tried to recreate the account on the smartphone but we have the same behaviour.
Moreover if the account is provisioned on the CA Mobile OTP desktop version, in that case the duration of the account is 10 year.
So again, i think that the account duration is not related to "CA Mobile OTP credential" validity , but is coming from another settings.
Did you have a chance to test in your environment and verify if in your case account duration is the same of credential validity?
Best Regards
Claudio