The main confusion for SOEC comes from a different definition of anode and cathode between fuel cells and electrolyzers. We have a chapter in the User Guide that explains this point. Unlike in the PEMWE and AEC models where notation is conventional, The SOEC notation inherited the very same notation as the SOFC. Naturally, it might create some confusion for the placement of potential boundary conditions.
The best way, to look into this issue consistently is by looking at the location of the OER (Oxygen Evaluation Reaction) and HER ( Hydrogen Evaluation Reaction). Please also consider prescribing voltage directly in the FC&E panel. The software will apply the voltage consistently, and then when everything becomes clearer, you can change to prescribing the potential boundary conditions directly at terminals.
Hope this helps and please let me know if you have any further questions.
Please note that the current densities in the order of 0.5 A/cm2 (5000A/m2) are perfectly achievable in solid-oxide electrolysis and fuel cells.