Symantec, Thawte and GeoTrust Extended Validation (EV) SSL certificates issued after November 28th, 2017 do not display the green address bar in Google Chrome browsers when they use the hierarchy below.
This is a Google issue and we expect Google to release a patch to fix this bug sometime in January 2018 (date subject to change).
Note that DigiCert SHA-256 Intermediate under the DigiCert SHA-256 Root is the hierarchy affected:
We advise you to replace these EV SSL certificates. Replacement certificates are signed by the DigiCert SHA-256 Intermediate under the DigiCert SHA-1 Root hierarchy and are not affected by this Google issue.