I started hitting issues quite some time ago. Such as generating long-term self-signed certificates for internal services.

  openssl x509 -req -days 7000 -in site.csr -signkey site.key -out site.crt

Lots of software on 32-bit Linux systems will choke on it when the experation date crosses 2038, albeit not major web browser as they saw the issue early on and addressed it.