Hi Francois,
We just released a hotfix Update (2.12.1-1) to fix this issue. Please run your maintenance tool to install the update.
After the update, you should again be able to use SSL in Release Mode.
By the way, if you are building for the App Store, please disable bitcode for the build as stated here in the Qt Bug Tracker.
Please let me know if that helps!
Cheers,
Lorenz