Definition - What does Heisenbug mean?
Heisenbug is a software bug that changes or alters its behavior when it’s being observed or undergoes isolation. Heisenbug can refer to any software bug with unusual behavior, particularly when its operation appears to disappear or change when it is being studied or worked on by a software program or debugger application.
Techopedia explains Heisenbug
The name of this bug is derived from a quantum physics law conceived by Werner Heisenberg, who found that human observation can have an effect on small particles, which can make their behavior seem unpredictable and studying them difficult. Heisenbugs are known to display very unpredictable behavior. Any attempt to debug or recreate a Heisenbug can make the bug disappear. Typically, a Heisenbug occurs as a result of uninitialized code in memory, where each function related with that value might act unusually.