Why would a woman who casually flirt with you talk with ur female friend??

We live near each other and we flirted few times she would smile and stare and act shy and dont talk much she is talkative with other ppl and she is an important person in the building when my female friend came to soend few days with me we used to sit at the building garden she walked near us and pretneded like ahe didnt see us i told my female friend about her then few days layer my female friend told me that she came and triend to have a friendly conv with her why did she do that??? Why she talked with her when i wasnt around??