LUT application: The most common mistake ruining primary corrections?

Hey everyone,

I'm a VFX artist, often stepping in after the initial color pass, and I'm trying to get a better handle on the grading process upstream. I've been working on a short film shot on an AMIRA, and the director loves a 'cinematic look,' which for them means a certain LUT. I'm trying to be mindful of the advice to avoid over-grading and, crucially, to prioritize skin tones.

I've seen some of the initial grades where the primaries are looking good, skin tones are balanced, exposure is solid (think SkyPanel S60-C light), and then the LUT goes on, and suddenly everything looks... off. The colors shift in strange ways, and those carefully balanced skin tones just turn waxy or sickly.

From your experience, what’s the single most common mistake you see beginners make when applying a 'cinematic look' LUT that just completely undoes all their diligent primary corrections?