[BUG]: Fix bug with pre epoch normalization
- [x] closes #36294
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

The fix propsed by @jbrockmendel worked.

Hope the test is in the right place