Animating Custom parameters from Construction Script in Sequencer

Hello, I have a strange issue with the animation of custom parameters in the Sequencer. Here is what I did: I createed an actor with a geo a material, a particle and a light. In the contruction script I created a bunch of custom parameters attached to the materials that I was planning to animate in sequencer later on. They all work properly, so the script and the names are correct. The problem is that if I create an animation track in sequencer, plug the actor and select the variables, if I animate them, the values won’t be considered. I did a quick test with the emissive only, going from 8 to 0. Nothing happens when I play the animation… but I can set the value the way I want and it will work statically. I’m quite a newbie of UE4, so I’m probably missing something obvious. Any idea? Many thanks!!