Why would someone avoid close proximity but later initiate contact?

My boss (f39) handed me (m31) some paperwork before heading back to her office. I was already on my way to grab a scan gun from the office next to hers, so she ended up behind me. Instead of following me directly, she changed course and walked around the dock until I came out of the office. Later, while I was taking notes, she walked past me and tapped my shoulder.