Found another reason for code signing to fail

I usually only build in Release mode, even when developing, both because of potential differences between release and debug modes and because of difficulties with dependencies in Xcode. I was always a little worried that this would bite me, especially with iOS, because here Release means building for distribution, right?

Surprisingly, it never did, until I installed an Xcode upgrade just now. Suddenly, my in-development iPad app stopped building for my attached device (development mode). The error was

"warning: Application failed codesign verification. The signature was invalid, contains disallowed entitlements, or it was not signed with an iPhone Distribution Certificate. (-19011)"

After doing all the usual certificate song-and-dance routines, I finally figured out that a flag was (now?) set in the build settings: "Validate Build Product", which was set to "Yes" for "Release" and "No" for "Debug".

Never having seen it before, I can't say wether the setting itself had changed or something in the environment, but setting it to "No" for "Release" as well fixed the problem.