cloud build can't build when assets are in native format

My take on this is maya PE isn’t installed on the build machines.

58413: [Unity] Updating Assets/art/game objects/paint.ma - GUID: 147e924ded0e445d68547c89428ed135…
58414: [Unity] Maya could not be found.
58415: [Unity] Make sure that maya is installed and the maya file has maya as its ‘Open with’ application!

Correct. We don’t install maya, blender, etc. on our build machines as it would be impractical to license/support all versions of these types of tools that people use. Your best bet is to export to something like FBX.

It’s mentioned in our FAQ here: Unity ID