Backport PR #27510 on branch 0.25.x (BUG: Retain tz transformation in groupby.transform)
Backport PR #27510: BUG: Retain tz transformation in groupby.transform
Hmm not sure why the tests didn't run. Did this need a backport? I think this was just an existing bug.  I guess https://github.com/pandas-dev/pandas/wiki/Maintainer-Overview#backporting isn't explicit about whether non-regression bug fixes should back ported. For smaller ones like this, I'm personally fine with it, but we should agree as a group. I had thought backporting was mainly for regression bugs, but I'm fine as well to backport this one.  we should disable codecov just generally :-<