Pug Behavior question?? Does anyone have an answer? www.chunkypugs.com

Hello all!!

I am a Pug breeder in South Carolina. Pugs have been my favorite breed for many years because of there personality. To my surprise, I recently had a female with very odd behavior and wanted to see if anyone had experienced this before. She came into her 2nd second heat, and when being around a male pug for the first time, she tried to mount him while he runs away from her. She acts very sexually aggressive toward the male Has anyone ever come across this before in any breed? I am curious as I have never seen this? Thank you!