Why is 'Re-run with same revisions...' limited to last few commits in git?

Running on version 10.0 I have a collection of projects, all of which depend on a central one called 'infra'. The other projects have artifact dependencies and not snapshots so whenever infra builds, the dependent projects get triggered to use the latest set of artifacts from infra i.e. include files, libs etc.

All was going well until this week. I had a pretty stable infra version about 2 weeks ago which was used for building the dependent projects. Unfortunately I didn't pin it and the cleanup process deleted its artifacts, though the history is there. In the meantime infra has moved on and there are 20 or so commits beyond that stable version.

If I try to rebuild it in order to get the artifacts back, using Actions -> Re-run with the same revisions... I'm shown the correct commit in the Changes -> Include changes drop-down, but the VCS root actually shows the very latest commit. If I go ahead with the build I'll get a build using the latest commit and not the one I asked for or was in the original build.

What's weird is that if I select a more recent commit, it is correctly selected. It's only if I go back more than a few days that the VCS snaps to the latest commit. I can' work out why and there's no obvious relation to pinned builds or any cleanup interval.

Anyone have any ideas for me to try?

Thanks