Media playlist controlled externally not working

Hi there.

My setup is as follows. Three surfaces playing videos. Each surface has its own media player applied as a material. Each media player has assigned a playlist with 4 videos each. My purpose is to set an external command to the playlist to play a specific video within its list.

In the blueprint:

I created a variable, and set it to be a media player, and dragged it o the blueprint. From its output, I placed an OPEN PLAYLIST INDEX and assigned to it the playlist previously created with 4 video
I then created a variable (to be controlled externally) and chose it to be an integer with values from 1 to 10. Called this variable ‘Screen_01_Playlist’ hoping that I could control the INDEX of the OPEN PLAYLIST INDEX with discrete numbers. Set 0 for video no1, set 1 for video no 2, and so on. Compile and save and when starting the simulation I have a video on all three surfaces as expected but when applying external values to the Screen_01_Playlist (the variable to change the index), nothing happens, the videos do not change. I enabled the debug filter and watched the value of the Screen_01_Playlist to see if the external source was sending the correct values and it was. On the external source when I set the value to zero, UE receives it and the Screen_01_Playlist displays it correctly, but when changing that value to 1 the video with that corresponding index does not start to play.

attached is a screenshot of this section of my blueprint. Any ideas?

Many Thanks