@plurb (View Post) Actually, this simulation can't handle over 5 layers of elements without using E-HOLE; E-HOLE prevents the BHOL formation.
plurb:
i have no idea how this happened since neut should be able to layer infinitely
Most likely, something else stacked with 5 or more layers of NEUT since you were playing with POLO, CRMC, and IRON.
thats not how it works !!!
You probably used replace mode on the NEUT
Issue (might actually be intended behavior) apparently reproduced: Put a large circle of IRON, then use POLO replace mode on its interior. After a few clicks, BHOL forms, and the POLO drains away.