QSettings serialization problems on Mac

QSettings can't save QColor using native OS format when app is running on macOS Sierra (10.12). ini format has no problems, everything is saved/loaded correctly.
with older OS everything is fine, at least in OS X 10.9

Tried 2 scenarios:
1. compile app in OS X 10.9.5 with Qt 5.6.2 and 5.7.0 and than run in macOS 10.12.
2. compile app in macOS 10.12 with Qt 5.6.2 and run it in macOS 10.12
results were the same

minimal test code to reproduce problem (full source is attached):

    QSettings system_settings;
    system_settings.setValue("test_app/color", cl);
    qDebug() << "system: src:" << cl << "loaded:" << system_settings.value("test_app/color").value<QColor>();

few words about incorrect saved data: its truncated after '(', no any bytes more. see last lines in 'settings.ini' from attachment

test program and its output from different OSes are attached.