It is well-established that the Minkowski limit of pure f (R) = R^2 gravity breaks down, unlike that of full Starobinsky theory f (R) = R + αR^2. We provide a novel interpretation of this phenomenon using the recent thermal analogy between scalar-tensor gravity and Eckart’s relativistic dissipative fluids. In this framework, we show that approaching the Minkowski background corresponds to a diverging effective "gravitational temperature’’ along certain non-stationary FLRW trajectories, while the gravitational temperature remains identically zero along the exact de Sitter family. This perspective naturally rephrases the strong coupling problem as a thermal singularity, demonstrating that R^2 gravity departs infinitely far from General Relativity rather than recovering it.