If I'm following the process correctly, when we do a Fedora compose, we build ostrees and put them in a repo at /mnt/koji/compose/ostree/repo/ with appropriate refs - e.g. fedora/40/${basearch}/silverblue for the Silverblue ostrees.

Unfortunately, it seems like the same repo and refs are used for nightly and candidate composes. So I think it's possible that if a candidate and nightly compose are running at the same time, one can actually overwrite the other's ostrees and cause problems. I think this happened to Fedora 40 Beta-1.3, because the Silverblue ostree installer actually deploys the ostree from the Fedora-40-20240313.n.0 nightly compose.