298226 2025-09-02 06:22:43 -0700 [iOS 18.6 Regression] Page load takes ~24s in Safari/WebView due to WebKit rendering/JS execution slowdown 2025-09-02 08:37:56 -0700 1 1 1 Unclassified WebKit New Bugs WebKit Nightly Build iPhone / iPad Other RESOLVED DUPLICATE 298222 P1 Critical --- 1 deepak.srivastava webkit-unassigned oldest_to_newest 2140200 0 deepak.srivastava 2025-09-02 06:22:43 -0700 Product: WebKit (Safari / iOS) Version: iOS 18.6 (WebKit 618.x – Hardware: iPhone 14 / iOS 18.6 (also reproducible on other iPhones) Steps to Reproduce Open Safari on iOS 18.6 (or any WKWebView in an app). Navigate to [https://www. dentsplysirona.com/de-de] Observe load time and rendering. Expected Results Page loads in ~2–3 seconds (normal load time on iOS 18.5 and earlier). Layout renders progressively, no long blocking tasks. Actual Results Page takes ~24 seconds to fully load. Rendering stalls before first paint. Same page on iOS 18.5 loads quickly, so this appears to be a regression introduced in 18.6. Additional Notes- Issue affects both Safari and in-app WebViews (WKWebView). Desktop Safari 18 (macOS) does not show this issue. Clearing cache/cookies does not help. Happens consistently across multiple sites with moderate JavaScript and CSS payloads. Possibly related to JS parsing/render pipeline regression introduced in iOS 18.6. 2140243 1 ap 2025-09-02 08:37:56 -0700 *** This bug has been marked as a duplicate of bug 298222 ***