In some applications where a relay is used they most likely use a “snubber network” which is supposed to protect relay contacts from overvoltage with inductive loads. The motor in the ALF is not using an inductive load and the “snubber network” can cause issues.  You can test it easily in two steps:

1. Disconnect the clamp “LH” so that only the “LC” clamp is connected to the controller and power “LC” – the actuator should move in one direction
2. Disconnect the clamp “LC” so that only the “LH” clamp is connected to the controller and power “LH” – the actuator should move in the opposite direction