Start/stop function with Auto-Hold (XC90 T6)

Hello, the start/stop function is basically reliable. However, I have noticed that the car starts again as soon as you take the foot off the brake, although Auto-Hold (Bremse) is on. In the manual it is written that the engine in this case only concerns once again, when you press the accelerator pedal, which also makes absolutely sense. I drove yesterday about 120 km over city, country road and highway and not once he left the engine off when I took the foot off the brake. That is very annoying, because I would like to take the foot off the brake. When we got the car new 2 weeks ago, he did not turn the engine on again, which should be so. Then a week later, sometimes not even yet, and now the engine is always on. Is there something here like in the Mercedes that is dependent on the braking force/duration that you spend? I tried it, but there are no differences. With my previous car (BMW 528i Ft) it has always left the engine function from Holt, maybe the other engine function from Holt to Holt.