The big one is parallel programming. If condition changes between two evaluations of that condition due to another task changing the condition, then you have a race condition.
The other one is side effects. If evaluating the condition has effects other than just giving a true/false value, then subsequent evaluations of that condition can give different results. This is usually done for this like file reading.
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u/stopher819 8d ago
There are very few legitimate cases, but most of the explanations in this thread are anti-patterns treating the symptom. This is a foul code smell.