@ajcvickers OMG. that's a DbContext, injected by DI (shared between the threads), I've no idea how I missed it! I think R# marked the _context as not in use (gray) so I overlooked it. \U0001f622 \tfor (var i = 0; i < 10000; i++) \t{ \t\tConsole.WriteLine("I'm an idiot and I'll stop bothering the EF team with my stupid bugs"); \t} Thanks Arthur and I'm truly sorry for wasting your time on this!