Plotly Express Line Chart Discontinued but Data Is Good

I have a dataset that has no problem regarding completeness and scale. All filled and same unit etc.

When I plot it alone in px.line(), it works fine like below

But when I plot it with multiple other datasets, then it looks like below (bright green colour curve discontinued)

df_ptf_ret = pd.concat([df_SL, df_SM, df_SH, df_BL, df_BM, df_BH, df_SB, df_SG_bis, df_BB, df_BG], axis=1)
df_ptf_cum_ret = pd.concat([df_SL_cum, df_SM_cum, df_SH_cum, df_BL_cum, df_BM_cum, df_BH_cum, df_SB_cum, df_SG_cum_bis, df_BB_cum, df_BG_cum], axis=1)

Does anyone know the reason?