In the most recent version of Streamlit the formatting of multiline markdown seems broken.
An example that works in streamlit 1.4.0 but does not display correctly in streamlit 1.5.0 +
import streamlit as st
with st.sidebar:
st.markdown(f"""| | Selection | All |
| :------------- | :----------: | -----------: |
| Images | 10 | 20 |""")
SOLVED: st.markdowm multiline formatting · Issue #4415 · streamlit/streamlit · GitHub