This is a known issue affecting vCenter 8.0 and has been fixed by vCenter 8.0 Update 3.
Workaround:
Manually remove the support bundle file under /storage/log after export.
Or create the support bundle from VAMI and download it. Then it can be deleted from VAMI.
Or create the support bundle from following URL.
https://<vCenter FQDN or IP>/appliance/support-bundle
Impact/Risks:
If /storage/log reaches 100%, vCenter goes down.