One sided heat exchange TL-G simscape

For the heat exchanger (TL-G) when running the simulation and plotting both the thermal liquid and gas temperatures the gas temperature spikes at t close to 0 and then instantly converges to the initial temperature specified in the heat exchanger. However, the thermal liquid temperature decreases over time as it should. What is the cause of this one sided heat exchange? Which parameters should i change?

[Yifeng Tang]

It's likely the initial conditions, possibly combined with the relative magnitude of the flow rate. Hard to tell without seeing the model and the parameters. Is it possible to post the model here for the community to better help diagnose your problem?