Lead source and Type in Prospect List

Hi there

I'm a new user of SugarCRM so my questions might be quite trivial to you. But I do need some help. I was browsing through the prospect list and have noticed:

1) How come some of the Lead Source displayed as blank even though this item has been filled up in this prospect's Lead?

2) Type column in the prospect list is also empty although their Lead's typology have all been filled up?

It'll be really great if someone can help me...

Thanks in advance

Song