Unable to set ep_star in MFiX GUI

How do I solve this issue: I am getting undefined ep_star error in my MFiX GUI model in my pursuit of developing a Hybrid DEM-TFM Model, I do set it in my Solid> TFM pane but it gets reset all the time and it gives me this error (image below)

Please look into my file and let me understand why is this error coming continuously in my hybrid model configuration. I’ve tried adding it via editing the .mfx file via an editor, but this error repeats itself via the GUI version

Please attach input files if you want us to look into this