px.timeline Incorrectly interprets x_end datetimes

The px.timeline function incorrectly generates the end times of the bar traces. The end times are placed before the start times.

Python version 3.8.6
Plotly version 5.4

Steps to reproduce:

import datetime
import plotly.express as px
t0 = datetime.datetime.now()
tf = t0 + datetime.timedelta(hours=1)
px.timeline(x_start=[t0], x_end=[tf])

print(t0)
print(tf)

Produces

2021-11-16 12:21:14.800827  # t0
2021-11-16 13:21:14.800827  # tf

The resulting figure is below. Notice that the right edge of the bar is the same as the start time, but the left edge of the bar is something else entirely.

The behavior is the same when passing a dataframe and column names. If you generate a scatter plot using the same datetime objects, the output works as expected (shown below).

Start at the px.timeline entry point and reproduce the issue with the datetime values shown in the report, comparing its bar trace coordinates with a scatter plot using the same values. Trace how x_start and x_end are converted into the figure, then verify that the generated bar has the expected start and end times and that the dataframe-and-column-names case also behaves correctly.