C++ What are the conditions of short circuit evaluation?

Question

if (i - word.size() >= 0 && dp[i - word.size()] && s.substr(i - word.size(), word.size()) == word)
    dp[i] = true;

i - word.size() >= 0 is the condition that I was using to prevent an out-of-bound indexing. The expectation was that if the condition was not satisfied, the equation would short circuit and the reference dp[i - word.size()] would not be happen.

But the reference happened regardless of the first condition. Only when I changed the code to the following, it started to short circuit.

int lookback = i - word.size();
if (lookback >= 0 && dp[lookback] && s.substr(i - word.size(), word.size()) == word)
    dp[i] = true;

Why does the second code short circuit while the first one doesn't? I've read that if the logical operators && and || are overloaded, short circuiting doesn't happen, but that doesn't seem to be the case here and I can't figure out why it's not happening.

Here's the full code for context

bool wordBreakFaulty(string s, vector<string>& wordDict) {
    int n = s.size() + 1;
    vector<bool> dp(n, false);
    dp[0] = true;
    for (int i = 1; i < dp.size(); ++i) {
        for (auto& word : wordDict) {
            if (i - word.size() >= 0 && dp[i - word.size()] && s.substr(i - word.size(), word.size()) == word)
                dp[i] = true;
        }
    }

    return dp.back();
}