Hmm, that does sound like unexpected behavior. Since it looks like you're using an older build of Axure RP, could you try updating to the latest build, 188.8.131.5277, to see if this scrolling issue is still present there? You can download the installer for that from our update page https://www.axure.com/update.
If you're still experiencing this issue while using the newest build, could you describe what you're seeing in a little more detail? Are you seeing that Axure RP's is unexpectedly zooming in and out even when you're not performing any zoom actions? Would you be able to post a video capturing the behavior?
You also mentioned that you were using a bluetooth mouse–which model of mouse would you happen to be using, and does the problem still persist when you disconnect it and use your computer's native touchpad instead?
Any additional information you can provide about the issue may be able to help with our investigation as well. Thank you!