vCenter 8.0 Update 3g introduces 5 differentiated alarms for certificates expiration, replacing the current generic one, which does not provide details on the specific VECS repository. The new alarms identify the certificate that is about to expire and provide a link to a KB with remediation steps.
vCenter Server 8.0 U3g or later
This is by design. See the second point of What's New section in VMware vCenter 8.0 Update 3g Release Notes
The alarm "Certificate Status", which exists in vCenter Server 8.0 U3f or before, is replaced with following alarms:
Certificate(s) in VECS TRUSTED_ROOTS store has expired
Certificate(s) in VECS TRUSTED_ROOTS store is about to expire
Data-encipherment certificate in VECS has expired
Data-encipherment certificate in VECS is about to expire
MACHINE_SSL_CERT certificate in VECS has expired
MACHINE_SSL_CERT certificate in VECS is about to expire
SMS certificate in VECS has expired
SMS certificate in VECS is about to expire
Solution user certificate(s) in VECS has expired
Solution user certificate(s) in VECS is about to expire
Note, the alarm names are upended with link to KB 385107 in GUI
Use the vCert tool to confirm which Certificate is expired and replace/remove it:
https://knowledge.broadcom.com/external/article/385107/vcert-scripted-vcenter-expired-certific.html