first click is ignored in iOS15

Hello
In my app, open a web page from unity and click the link in it to get that information
I receive it on the application side and open the corresponding page in a new window prepared by the application.

I'm having a problem with iOS15 and the callback when I click the link doesn't come back.
When I registered click with addEventListener on the application side, the callback came to come.
However, the first click is ignored and the second click only responds.

Are you having similar issues with iOS15?
Also, the source is as follows, but please point out any problems.

===================================================================================
html side
＜a href="javascript:void(0)" onclick="Unity.call('###########')"＞

application side
#if !UNITY_EDITOR_WIN
m_WebViewObject.Init(
　　cb: (msg) => {
　　　　Debug.Log(string.Format("CallFromJS[{0}]", msg));
　　　　if(callback != null) callback(msg);
　　},
　　err: (msg) => {
　　　　Debug.Log(string.Format("CallOnError[{0}]", msg));
　　},
　　ld: (msg) => {
　　　　Debug.Log(string.Format("CallOnLoaded[{0}]", msg));
#if !UNITY_ANDROID
　　　　m_WebViewObject.EvaluateJS(@"
　　　　　　window.addEventListener('click', function() {
　　　　　　　　if (window && window.webkit && window.webkit.messageHandlers && 　
　　　　　　　　　window.webkit.messageHandlers.unityControl)
　　　　　　　　{
　　　　　　　　　　window.Unity = {
　　　　　　　　　　　　call: function(msg) {
　　　　　　　　　　　　　　window.webkit.messageHandlers.unityControl.postMessage(msg);
　　　　　　　　　　　　}
　　　　　　　　　　}
　　　　　　　　} else {
　　　　　　　　　　window.Unity = {
　　　　　　　　　　　　call: function(msg) {
　　　　　　　　　　　　　　window.location = 'unity:' + msg;
　　　　　　　　　　　　}
　　　　　　　　　　}
　　　　　　　　}
　　　　　　}, false);
　　　　");
#endif
　　}
);
#endif

m_WebViewObject.SetMargins(left, top, right, bottom);

m_WebViewObject.SetVisibility(true);

m_WebViewObject.LoadURL(Url.Replace(" ", "%20"));

Start by reproducing the iOS 15 behavior with the HTML onclick handler and the application-side EvaluateJS click listener shown in the report. Compare the first and second clicks and trace whether Unity.call reaches the callback; done means identifying the cause of the missed first callback and documenting or fixing the behavior.