What version of Map Pilot are you using? Can you please take a video and send it to us at firstname.lastname@example.org so we can see what is going on?
You should be pressing and holding to draw the first 3 boundary markers and then dragging the midpoint boundary markers to form your survey area. You might be doing something else but we would like to address the issue if possible.
Also, try using version 4.0.4 which is the latest release.