Open Radar

 
I started creating this bug report before iOS11 beta 6 which seems to have fixed this issue, but as I haven't seen an openradar bugs, I wanted to submit the report anyway just in case this issue comes back. 

On iOS 11 beta 5 & below (but only on iOS 11, not iOS 10), our mobile application has had WKWebView display issues when loading local web content. From doing some investigation, it looks like scripts can non-deterministically sometimes not be loaded sometimes upon initial page load of the index.html. I have come to this conclusion by running on a device & inspecting the webview from Safari on mac and under the resources tab, it show's that some of our script files are shown to not have been loaded. This theory is supported by the behavior we are seeing as it seems like our JavaScript is not actually executing when we see this bug.

I have attached some screenshots of mac safari inspecting the webview on iOS.

I tried recreating a standalone project to reproduce, but did not manage to identify what might be causing this. Simply our application loads a local file and resources in a view within our application that is loaded during a UINavigationController transition to that view.