Objects randomly Switching to Matte

[gummipolarbear]

I'm having an issue where my objects randomly switch to Matte when rendering high resolution images. Not sure what's causing this, could it be a bug?

Also when saving my file to png it sets my ship as an alpha channel and saves only the ocean from Phoenix.

[hermit.crab]

Sounds as if you have the Render Mask option enabled (Render Setup > V-Ray > Image Sampler). Otherwise, do send the scene.

[gummipolarbear]

Sounds as if you have the Render Mask option enabled (Render Setup > V-Ray > Image Sampler). Otherwise, do send the scene.

Whatever was setting my object to Matte also set it to have alpha value of -1. Still not sure why it gets switched though.