messages app not working right

My friend has an ipad and an andriod phone. I used to be able to text her on her phone and imessage her on the ipad. This would show up as 2 threads in my message app.

Since a recent update these two have now combined into one thread. Very annoying but doable. It will default to which ever one she used last. If i need to change it I can tap on her picture at the top and with 4 clicks I can switch back and forth.

Since today I noticed that if it defaults to imessage I can't change it back to text. Even if I choose her phone number it is still blue and says imessage and she doesn't get it on her phone. The only easy way I found to fix this is to delete the thread and start a new one. I don't want to keep doing this.

Has anyone else had this issue?