Hi Sophia,
as far as the update goes, its Build:233,Release: 2017.3 Update - Date : Mon 10/31/2016
in terms of inventor projects, I am using vault, so I only have one project that manages the entire work-space with unique file naming system pushed through vault.
this is puzzling me as well and I totally understand your point to reproduce it and diagnose it from there, but I just dont know how. I can give you a clue and it might help Autodesk team with identifying where the issue is coming from,
if I open my standard(mm).ipt , go to document settings, change units back to "in" and "lb" from "mm" and "kg", save the file and close it, the error message disappears, so whatever it is, units causes that "default modelling" mismatch in style. as soon as I change the units back to metric, it pops up. to be honest with you I cant think of anything else that I have done after we fixed the issue and I also contacted our re seller and let them know.
Having said that, the product is running fine otherwise, I can shut the message up for the session and it wont bug me anymore, but I just wanted to contribute to a have a better , more reliable problem free product in future versions.
Sincerely
Ali