Fix parsing corner case closes #19382
- [x] closes #19382
- [x] tests added / passed
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/19529?src=pr&el=h1) Report
> Merging [#19529](https://codecov.io/gh/pandas-dev/pandas/pull/19529?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/bc1d0273cd4b7ddf348feff5f46b6eb114ea04c9?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/19529/graphs/tree.svg?token=eZ4WkYLtcO&src=pr&height=150&width=650)](https://codecov.io/gh/pandas-dev/pandas/pull/19529?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #19529   +/-   ##
=======================================
  Coverage   91.62%   91.62%           
=======================================
  Files         150      150           
  Lines       48714    48714           
=======================================
  Hits        44633    44633           
  Misses       4081     4081
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.99% <ø> (ø)` | :arrow_up: |
| #single | `41.75% <ø> (ø)` | :arrow_up: |


------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/19529?src=pr&el=continue).
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> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/19529?src=pr&el=footer). Last update [bc1d027...0af64f6](https://codecov.io/gh/pandas-dev/pandas/pull/19529?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 > The conversion code for datetimes is still all over the place because tslib.pyx still exists, would be happy to remove that.

Yah, I've been holding off on that because there are small differences between array_to_datetime and the Timestamp constructor that I'm hoping to un-difference, then share the implementation. thanks. happy to have a cleanup in array_to_datetime, but that's a separate PR