[stunnel-users] Response not received

Here is current setup. Linux Server - Application ==> Stunnel in Client mode ==> Network ==> F5 havingTLS cert to decrypt traffic.

We are runnign Stunnel in client mode to encrypt traffic with detination F5. F5 is equipped with TLS cert which decrypts traffic. Setup is working fine but we see some 0.2% traffic is impacted where Stunnel calling app in client side does not receive response. We are not running Stunnel on Server mode on destination. Packet capture does not show any abnormalities. Stunnel used by use is 4.62 coming out of Redhat distribution. We are clueless on traffic drop. Anyone with similar experiences can help?