Translation not working in a model constructed with QVariantList

All the translations are working well except for one particular case :

When I fill a ComboBox with a QVariantList of QVariantMap, items are not translated.

Il fill the model with QList<QVariantMap> and each QVariantMap is constructed with :

map.insert("id", QVariant::fromValue(myObject));
map.insert("name", toString(myObject));

where myObject is an attribute from an enum class and toString(myObject) is a function that transforms the attribute into a readable string to be displayed in the ComboBox.

For example, toString(Enums::Encryption::SRTP) returns QObject::tr("media_encryption_srtp")

I can see "media_encryption_srtp" value in the translation files and the translations are actually filled but all I can see in my UI ComboBox is the value "media_encryption_srtp".

Thank you for your help.