Regression raising Error when having dup cols with single dtype for read csv
- [x] closes #42022
- [x] tests added / passed
- [x] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing.html#code-standards) for how to run them


regression on master, so no whatsnew
> is this for 1.3?

looks like it Yes this is a regression on the rc thanks @phofl  @meeseeksdev backport 1.3.x Something went wrong ... Please have  a look at my logs.