If you smash subatomic particles together and a shower of GUIDs, ints and alien strings, we know we're in a simulation.
Actually, tho, how is there any difference between "the universe is math (i.e. a computer) doing physics problems" and "we are in a computer simulation running doing physics problems". One is *sui generis,* one has an infinite regress problem (levels of reality).
And in both cases they should have bugs and design mistakes.