It’s intentional. The general idea is to make it easier to detect fraudulently issued certificates. LetsEncrypt submit all certificates[0] to Certificate Transparency[1] logs.

Chrome won’t actually show the green address bar for EV certs unless a CT proof is provided along with the certificate[2].

[0]https://letsencrypt.org/certificates/

[1]https://www.certificate-transparency.org/faq

[2]https://blog.digicert.com/certificate-transparency-required-...