Betta Fish: Is this normal?

I got this female elephant ear betta about a month ago. I clean her tank every week and do a 25-50% water change usually. I cleaned her tank yesterday and switched out her plant tunnel to this rock tunnel and now she’s suddenly building a bubble nest? I thought only males did that? Am I doing something wrong? Also she used to be white but now she’s turning more blueish/reddish is that also normal? You can’t see her color clearly in the first photo and the 2nd photo is when I first got her.