Configure the Harmony to use the Microsoft Media Center (MCE) profile, this will work with LibreELEC out of the box.
We dropped a bunch of remote configurations in LibreELEC 9.0 that were buggy and/or caused issues (the Zotac config is one of them).
so long,
Hias
Alright, I gave it a shot and it works like a charm now, thanks a lot!