Problem with Option + Backspace in Pages

Very frequently when I'm working in Pages and I try to do backspace several words at a time Pages will select the next several lines and delete those as well. This happens rather frequently, and will catch me off guard. Often times I'll be working fast paced on something, option + backspace to delete several words for rephrasing or something and be frustrated by the fact that Pages highlighted the next few lines and deleted those as well.

This is easily remedied by cmd + z, but is there a way to disable this? It's very frustrating and I would like to keep this from happening. I've attached a screen shot of the problem. Here I've started working on an report and am working with bullet points, this doesn't happen only with formatted text, but also with normal just plain text randomly. I can't seem to identify a pattern.