What factors affect the minimum time to go from point A to point B?
It looks to me like your airplane, starting with a very low velocity, is trying to climb a height of 46m (61m - 15m).

Because it has a low initial velocity, your basic choices are:


Start climbing immediately, demanding engine power both for velocity and climb rate, and climbing very slowly.
Fly level for a period of time to build up velocity, then begin the climb.
Use gravity and engine power together to get more velocity quickly, then begin climbing at a much faster rate.


The velocity you need to achieve is called $V_y$, or best rate of climb.
Based on the Yellow color on the main segment of the climb, it looks like this plane's $V_y$ is about 26 $m\over s$.

It looks like your software package chose #3.  While it makes intuitive sense, without the math behind it, I cannot tell you the details.