Just by searching on the web when I came across this issue and found that can be an Apple error (no bugs or crash are appearing with this error in my app).

If the error occurs only when you set up the UIWebView on your app. I would check if the app has configured correctly the “App transport security Settings” in your .plist

if you inspect your .plist you can add it by hand like:

<key>NSAppTransportSecurity</key>
<dict>
    <key>NSAllowsArbitraryLoads</key>
    <true/>
    <key>NSExceptionDomains</key>
    <dict>
        <key>add-your-site-here-if-needed</key>
        <dict>
            <key>NSExceptionAllowsInsecureHTTPLoads</key>
            <true/>
            <key>NSIncludesSubdomains</key>
            <true/>
        </dict>
    </dict>
</dict>

This happens to me also when I added some third-party code like FirebaseSDK. And it suddenly stops appearing after I setup correctly my URL schemes for all my environments. So I´m assuming that this error appears when something is not fully/correctly implemented like in a snowball effect by Apple side code.

NOTE: You can also try to go back a few steps back on when the error occurs to narrow down the possibilities of occurrences of this error.