Problems with making "stability window of material" funtion

Hi all,

I am trying to make stability window of material with pymatgen.
And this is my code:

It works successfully with K compounds, but if I put Li or Na compounds in the fuction, it returns wrong values.
I found that ‘analyze_pd’ funtion return not only stable entries, but also unstable entries, if I put Li or Na compounds as the input value.
But I cannot find the reason why…
Are there some difference K and Li or Na compounds in the pymatgen?

If you know the reason please help me :frowning: