BUG: Series read_json tries to convert all column values to dates even when using keep_default_dates=True, if one column has an na value FIX
- [ ] closes #49585 (Replace xxxx with the GitHub issue number)
- [ ] [Tests added and passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#writing-tests) if fixing a bug or adding a new feature
- [ ] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).
- [ ] Added [type annotations](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#type-hints) to new arguments/methods/functions.
- [ ] Added an entry in the latest `doc/source/whatsnew/vX.X.X.rst` file if fixing a bug or adding a new feature.

As noted here, this isn't the solution, sorry https://github.com/pandas-dev/pandas/issues/49585#issuecomment-1342263806 > As noted here, this isn't the solution, sorry [#49585 (comment)](https://github.com/pandas-dev/pandas/issues/49585#issuecomment-1342263806)

closing then, but thanks for your pr