A function that returns a status/amount is called and its return value is discarded (not a low-level call, but e.g. an ERC20 bool, a queue pop result, or a sub-call success). Failures or partial results go unnoticed.
// pool.remove(id); // returns bool success, ignored // remove() returns false (id not found) but the caller proceeds as if // it worked -> inconsistent accounting.
bool ok = registry.tryRegister(x); require(ok, "register failed");
Largest recorded losses in the same failure class — related, not the same bug:
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