Out of curiosity, is this bug related to CPU cache? I don't know really anything about how CPU's work internally, however. It just "feels like" it's applying a bunch of instructions very quickly but ignoring the internal clock if that makes any sense.
For example, the CPU percentage counter in Activity Monitor was around 3,000,000. If there was a loop to increment the CPU usage counter, it sounds like it incremented it so fast that the thread that reset it didn't run since it wasn't scheduled to run (as it only runs every few seconds.) Again, this is just pure speculation and if anyone knows otherwise please let me know!