Add_hline resetting x-axis to 1970

I am trying to plot from a dataframe with a DateTimeIndex (sample: 2020-11-11 00:00:00+00:00, type: pandas.core.indexes.datetimes.DatetimeIndex) and want to add a horizontal line.

When I use add_hline, the plot resets the x-axis to 1970-01-01, whereas my earliest date in the dataframe starts in 2020. When I remove the add_hline, the plot shows normally.

Iā€™m not sure what the issue is, any help is appreciated!