Cookies set by AJAX responses not accessible by JS when using WKWebView

Hi, we have really weird issue with one of our website embedded into iOS app using WKWebView. The website has CSRF mechanism implemented and is using some AJAX calls when user interact with it and in response some cookies are returned. Then the JS code wants to access these cookies to set proper value for next request header. Unfortunately when using document.cookie JS command these cookies are not there. However they are sent within another requests and I can see them from Safari Developer Inspector connected to my device or iOS Simulator. Another interesting thing is that the same website and solution works fine on Safari browser and with SFSafariViewController displayed inside our app. We've tried using various things for WKWebView configuration like nonPersistent data store, but without success. Does anyone have any idea how to deal with such issue and why it doesn't work with WKWebView?

Cookies set by AJAX responses not accessible by JS when using WKWebView
 
 
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