Weird teething behavior??

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So, my January 8th baby has been doing something kinda odd the past couple days. I haven’t breastfed her since she was a month old, she’s been formula fed since then. She got two teeth at 6 months old & now at almost 9 months she’s cutting teeth again. The last couple days she has been determined that she’s going to bite the top of my boobs. Even if I wear a high collar shirt she tries. Is this normal??