My Foster Daughter

Hi, I need advice. 2. 5 year old girl move from other home to our home 3 months back. Her bios are addict , and she has severe food allergies and top of it severe eczema. She requires daily skin care regime and home prepared organic food. She is needy and requires lot of medical and personal attention. We have intentions of adopting her in case bios don't show improvement which they are not at this point. But we recently noticed one of state worker who picks her and drops her off for visitation seems be interested in her. Every time she picks her up and drives her by the regional office she would talk to my daughter and tell her about my daughter moving to her and she being future mom and now foster daughter talks about her all the time and moving in to her house etc. This is conflict of interest. I have not talked to my case worker yet about this . i don't know what to do. Because if state worker was interested , she should be opting it for long back. My daughter was moved twice once from Bio and once from other family ( Very nice family - Their kids did not go along with her ) . Please help. Any suggestions . Help. thanks