The problem is in fact present, because the CLB Thrust will not respond to the acceleration altitude when it reaches the acceleration altitude and will remain in GA mode. Thus, the speed can indeed screw in, but does not lead to an acceleration.
One can now manage by activating LVCH or VNAV at the acceleration level or as soon as possible. I have tried this several times now, but have not succeeded in the normal procedure. Rather, I noticed again that the autothrust has problems with keeping the speed during turns. Despite specification of e.g. 180 kts with Flaps 5, the speed dropped to the break of the current. At the start in the course round the chosen height was often ignored despite autopilot or at least clearly exceeded.