Asset reflection is likely on by default (I presume it is at least) and can cause problems a lot of the time.
What happens is if two files have the same name in asset reflected folders and they get used I believe that can cause this issue, but I’m not sure it’s been a while, prefix all my files and have strict naming conventions now. It’s a pain but its good habits so, as with all things… it is what it is 
Take a look at the troubleshooting steps here and see if that helps. 