ALT key not working on Chroma Studio - Razer Blade 15 Advanced Model (2019)

Hey there, first of all, sorry for my english. Now to the point, this machine is a beast, working perfectly all around: there is just one little problem that could be Synapse-related (???): I can't apply any effect in Chroma Studio on my left-ALT key. Mind that the key is correctly typing and when I setup Quick Effects on my keyboard (every style I choose), that key lights up. Also, when I create a new advanced profile, Chroma Studio applies the basic Spectrum Cycling, and that key is working as well in that case. The problem happens whenever I try to change anything on it. It goes off, black, can't change or swap back to previous colors. Things done so far trying to resolve (without success): reinstalling Synapse, updating every single component (bios, firmware, etc.). I've done a new Windows installation. Nothing worked so far. EDIT: I've also tried to make a new account, also didn't work. It's clearly not a hardware problem. Attached, two screenshots, first one is the key working when I just open Studio with the standard profile, second one when I try to apply any effect on left-ALT. Any solution about this? Cheers