git changelog outputs all commits in only one repo

When I use git changelog -x in my old clone of the pandas repo (https://github.com/pydata/pandas), it shows all commits, not as usual the commits since the last tag.

I cannot reproduce it with a newly cloned repo, only with the one I already have.

Another interesting fact (in that broken? repo) is, that git changelog takes the last tag as outputted by git tag and shows everything from that until today (e.g. no 0.4 shown):

v0.10.0
v0.10.0b1
v0.10.1
v0.11.0
v0.11.0rc1
v0.12.0
v0.12.0rc1
v0.13.0
v0.13.0_ahl1
v0.13.0_ahl2
v0.13.0rc1
v0.13.1
v0.14.0
v0.14.0rc1
v0.14.1
v0.15.0
v0.15.0rc1
v0.15.1
v0.15.2
v0.15.2pre
v0.15pre
v0.16.0
v0.16.0rc1
v0.16.1
v0.16.2
v0.17.0
v0.17.0rc1
v0.17.0rc2
v0.17.1
v0.4.0
v0.4.1
v0.4.2
v0.4.3
v0.5.0
v0.6.0
v0.6.1
v0.7.0
v0.7.0rc1
v0.7.1
v0.7.2
v0.7.3
v0.8.0
v0.8.0b1
v0.8.0b2
v0.8.0rc1
v0.8.0rc2
v0.8.1
v0.9.0
v0.9.0rc1
v0.9.0rc2
v0.9.1
v0.9.1rc1

The last tag in the output is v0.9.1rc1 but there is also a master / 2013-02-17 line, one which names my branch (API_additions / 2013-10-15) and three n.n.n / 2016-01-19...

Start with the git changelog entry point and reproduce the command against the reported old pandas clone, comparing its tag list and branch output with a fresh clone. Trace how the last tag is selected; done means git changelog -x reports commits since the correct latest tag without including the repository's full history.