@DTS Engineer I can second the issue and suspect it to have something to do with restore/update from an older iOS device when the certificate is already present on the older device. Here are the steps to reproduce the issue for me: Bought a new iPhone 16 Pro Restored the iPhone 16 Pro (iOS 18.1) from an iPhone 7 (iOS 15.8.3) backup The iPhone 7 already had a custom (working!) root CA certificate installed The root CA certificate was not present after the restore on the iPhone 16 Pro Re-Installed the root CA by (1) downloading the certificate via Safari and opening it via the Files app on the iPhone 16 Pro Profile is successfully registered in settings -> general -> VPN & Device Management on the iPhone 16 Pro No triggers option to trust the certificate in Settings / About / Certificate Trust Settings on the iPhone 16 Pro though Unfortunately, I cannot file a bug report because the login via URL "applefeedback://start" to the Apple Feedback app does not work with my Apple ID login.

Based on your bugs we think we understand what’s happening here. As folks have noted on this thread, it seems to be related to updating from iOS 16 or earlier, either directly or from a restored backup. The system is not correctly handling the migration from an older form of its internal data structures [...] … I don’t have any info to share as to when this will be fixed [...] Glad to hear you found the root cause on your side. Take the time to properly fix it, no worries. Let us know if you need additional input. I would also like to thank you for your open communication regarding the problem and bringing awareness of it to the developer team!