nucleosynthesis - What could explain the presence of Promethium in stars?

[This is pretty much a copy and paste job from Technetium question but I wanted to add this one in case there was some other explanation] So, I understand that PM doesn't exist in nature [though, I don't know why every reference I see regarding PM says that and then goes on to state that it is found in some stars...] but, if that's the case, then why is it found in some stars? This element doesn't fuse in stars (I think, I found a graph saying that it does) so it has to be left over from supernovae. Lastly, how many stars have been discovered that contain promethium? Thanks much.