Dates in streamlit

I’m using Streamlit to show my python output file instead of using Jupyter Notebook. I was converting object columns to datetime, when using jupyter notebook, the pd.to_datetime() command convert strings and left the NaNs as-is

But when using the command st.write() to show the output, it was

The first values of "started_at_ahc" was null values but streamlit filled it with Sep 21, 1677 2:17 AM

Why does this happen?