At official break-in revs U get low speed, low waterflow speed but plenty of heat from the combustion and low airflow over watercooler - U are bordering logging the engine, which generates more heat as it has to pull hard and burn more fuel to keep even low speed.
Letting the engine rev freer, U get waterflow up to speed and get airflow to the cooler - and as engine doesn't have to pull that hard, it generates less heat.
Living in a metropolis, I drive mostly in stop-and-go traffic. Which lowers airflow and waterflow, thus the fan will turn on every now and then.
Can happen at a red light - or at low speed.
Doesn't matter - as long as the fan works correct, then it's just a matter of short time before temp goes down again.
How many bars ? Doesn't really matter and may very well be hard to compare between our bikes as it seems that the temp gauge isn't calibrated; each gauge sounds to give different readings.
We need absolute temp to compare.
My Ninja 250s did the same - my KLX250S too.
Just be happy that Kawi now finally has designed the fan outlet so that it DOES NOT send bloody hot air out over your right thigh !
On the KLX, I allways knew when the fan turned on, at least when it was warm enough to ride in jeans