Originally Posted by
the810
At what step do you stop the dummy booking? If you go past the passenger information, e.g. to check the seat map, the system will create a reservation and thus remove a seat from inventory. That may cause temporary price hike until the reservation expires.
Otherwise it's just a coincidence.
On no occasion did I take it past the results page. But if I searched say >10x in a day it seemed to go up the next day. Coincidence seems likely but I might give it a go on another route on another date and see if it has an effect to support my theory.