Can confirm the same bug on various machines with various different setups. Issue happens only on Tahoe 26.3, but with Xcode 26.1.1, Xcode 26.2 and Xcode 26.3 RC. Issue happens with public projects and proper setups of SSH keys, known_hosts, Xcode settings etc. Issue doesn't happen for all projects but for those affected it happens even on a first checkout with a fresh Xcode install that has never seen that project before. Haven't figured out exactly what triggers the issue, but projects that have dependencies that have dependencies again seems to have a higher likelihood. Only mitigation is to run xcodebuild -resolvePackageDependencies via terminal before opening the project, that still works fine under macOS 26.3, resolving directly in Xcode always fils with Failed to verify SSH fingerprint.

Sadly WCSession.default.updateApplicationContext(...) is again broken in a simulator context for watchOS versions after 7.2, and also for all watchOS 8 beta versions so far. FB9547733 includes some detailed information about the situation with Xcode 13 / watchOS 8 beta.