I'm also having this issue, coming from production app, we are not able to reproduce. The only thing we know is that it's from CoreText and here TDecorationRun::CalculateGlyphIntersections. It's very specific to some users, about 50, but we already have 500 crash events for those 50 unique users.

Hello, We don't have specific points of the app code where it may be crashing, since it's random, we already seen code crashing at very different locations around the app. Currently, about 5% of our users base is having this crash, also another detail, we are seeing this around different versions of iOS, not specific to iOS 18 or 26. We suspected at first about the compiler of new Xcode 26 (since this was the first version compiled with new Xcode), but it seems it is not that. We have sent a new build out today, compiled with Xcode 16.4, but no luck, still crashes. I'm attaching 2 screenshots, from the crashing stacktrace, one from Sentry and the other one from Xcode crash reporter directly. Also, attached the .crash file with the full stacktrace that can be found at Xcode. 2025-10-01_14-37-42.7083_-0500-2937c5ddef763873e9e26e42e243231a23e27df5.crash

@DTS Engineer we have been able to detect the crash issue. It's happening indeed on rendering of an UIButton, and not something related to CATransaction or race conditions between threads. The issue happens when using a parenthesys as part of text in a button title, that is using a custom font (Uniform-Medium) and we have the Acessibility option Button Shapes enabled. If we do remove the parenthesys, as we did in order to fix the crash for our users - it works normally. We have created a demo app here, it's hosted on GitHub, and it has more information on the README file. But basically running the demostration app with the accessibility option Button Shapes enabled it's enough to see the crash happening. Thank you for your attention.

Hi @DTS Engineer thank you for your response. Yes, I've created it yesterday - here it is https://feedbackassistant.apple.com/feedback/20784276 it contains all the same data as here and the sample project too. Thank you!