I saw that you added the update.php string to the if clause on line 70 to so that the settings version is actually being set when we are checking for an update. Unfortunately you seem to have gotten the wrong $pagenow value, the correct value for $pagenow when your on the update page is update-core.php.
When I now changed the string into update-core.php it no longer prompts you to update 🙂
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