I am planning to go to Germany on tourist visa, so I have applied for a Schengen visa. I booked flights to Germany, not actually paid for the tickets but reserved for two days. Will it cause any issues as booking gets cancelled after two days ?
Do not buy the plane tickets until you receive your visa.
The German mission is well aware that reservations expire before your visa application can be processed. They don't really care about that. They are evaluating whether your proposed itinerary makes sense in light of your personal circumstances.