Thank you to the people that commented, and the different options, it isn't an architecture issue as I thought but as Guru-Stron suggested it's most likely an unawaited Async call.

I was doing a saveAsync without awaiting, completely my fault:

 _wrapper.RepositoryContext.AddAsync(dbSession);
 // save in the database
 _wrapper.RepositoryContext.SaveChangesAsync();

Changed to:

await _wrapper.RepositoryContext.AddAsync(dbSession);
// save in the database
await _wrapper.RepositoryContext.SaveChangesAsync();

Please upvote his comment, not this answer.