EOS C70 Vignetting with CN-E30-105mm T2.8 L S

[lydiacornett]

Hi all, I'm a documentary filmmaker with a Canon C70. I'm trying to use the C70 with the CN-E30-105mm T2.8 L S and a Mount Adapter EF-EOS R 0.71x, but I'm getting a lot of vignetting with the widest focal lengths. Is this normal?