Synthetic Identity Propositions

As has been previously suggested, the attribution of 'informativeness' to a Fregean 'Proposition' runs the unwanted risk of exposing it as a Proposal, the personalized, purposive context of which has been suppressed. To avoid that complication, the prototypical Fregean puzzle can be rephrased as 'How can an Identity Proposition be synthetic?', the solution to which is that its referent is one and the same, but its terms are distinct, or, equivalently, e. g. in 'A = B', 'A' and 'B' have the same 'Reference' but not the same 'Sense'.  However, the attempt to generalize the favorite examples of that theory exposes a different weakness in the model.  For, 'The red object is a spherical object', has the much less puzzling explanation that one and the same object can have two different properties attributed to it, just as 'The Morning Star is the Evening Star' reduces to 'One and the same object sometimes appears in the morning, and sometimes in the evening'.  So, to further purify Fregean Philosophy of Language, i. e. by better depersonalizing its Propositions, seems to only trivialize it.