Effective March 1, 2018, 3-year (and longer term) certificates have been deprecated by the CA/Browser Forum Ballot 193. Going forward, any public-facing SSL/TLS certificate can have a maximum lifespan of 825 days.
In advance of Ballot 193's effective date, we built a tool to resend Domain Control Validation (DCV) emails to WHOIS contacts concurrently with notification emails where our system showed multiple pending 3-year certificates. However, due to a reporting error at the beginning of the process, we sent some duplicate emails. The duplication existed only in the email process. We have updated the tool to avoid sending multiple emails to customers per domain. Nevertheless, we apologize for any inconvenience we caused by sending these duplicate emails.