After trying different things, it turns out it was VS cache. You can resolve it by deleting the cache files located in:
C:\Users\your.name.here\AppData\Local\Microsoft\VisualStudio\14.0\ComponentModelCache
I closed my project, deleted the files on that path and reopened my project, cleaned the solution and built it again and the problem was solved
The files will be recreated when you next launch Visual Studio