BUG: alignment changing index on input series
- [x] closes #33671
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

also i think this needs a whatsnew bug fix reshaping note whatsnew added + green updated + greenasitgets