The CentOS project is using different trackers, based on which team needs to be in charge of the issue to solve. While we (CentOS Infra) are ourselves using the pagure.io one (hosted and maintained by Fedora), there is only one that we are hosting : bugs.centos.org.
Hosted by Fedora and used for infra tracker. Url is https://pagure.io/centos-infra/issues
Hosted by Red Hat and used for everything related to CentOS Stream :