Since version 4.6, Max has been creating files called oobo in the system temporary folder. Normally these files should be deleted when Max quits, or shortly thereafter, but it’s possible that if the program crashes or you have a permissions problem on your system that the contents of the temporary folder will appear in your trash. It turns out to be fairly hard to write a program to delete a folder on the Mac, and the code we wrote to do so was unreliable, so we decided to chop that code and count on the system to handle it for us. This is equally problematic, as for a certain small number of people, an accumulation of oobo files occurs. I’m not sure why the Mac OS thinks it needs to "save" anything "temporary" by putting it in the trash. I’m just speculating here, but there are a lot of weird things in the Mac OS that are there only to support Microsoft applications. This might be one of them.
Sorry I don’t know more about this. If it is 100% reproducible on the new MBP that would be very helpful in trying to track down the mystery.