When I launch P3dV4, the application screen asking "Do you give permission to Virtuali Couatl engine this time or always " NEVER came up for the 'coutal engine or the Add on manager .
With "application screen" you mean the antivirus ? Since P3D doesn't have a trust screen window (like FSX), I assume it's the antivirus so, if you are seeing that question, it clearly indicates you have NOT exclude the Addon Manager folder correctly, otherwise the antivirus wouldn't have made the question.
Unless, the antivirus is so bugged, that is ignoring your exclusion settings. Wouldn't be the first time that an antivirus trusts more its own flawed heuristic than the user settings.
Re-check your exclusion and, eventually, uninstall that defective antivirus.
As I've said in my previous post, we sent a false positive report to Trend Micro, then haven't even replied to it.