Can happen. KUKA does not guarantee the automatic speed reduction works in 100% of all cases. The details how it works and what might help depend on software versions which unfortunately you do not tell us. Also how well it can work depends on the used motion commands (Spline works best). But the robot will never reduce its velocity "inside the safety room" as your topic states. It will try to reduce before entering the forbidden zone. And depending on many factors (current load, current positions, current velocity, current accelaration, ...) this might not be possible fast enough to be below the limit when entering the forbidden zone.
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