Those coolants should last a lifetime. Highly suspicious for a lemon

 

According to Hyundai Manual, coolant is good for 200,00 km (125,000 miles) or 10 years. After that replace every 40,000 km (25,000 miles) or 2 years.

 

From the repair manual it appears that Hyundai has a proprietary (I can't make out a brand name on the instrument) device for its leak testing. As you might imagine, it's not a simple process...draining, disconnections, pressurizing with helium, the leak tester...
I am trying to remember if some ICCU failures were internal-leaks related..?..

In any case you should contact your service center, and monitor your coolant level closely until you determine it is or is not still leaking, and proceed accordingly.

[Cooling Mode (Battery Cooling Mode)] (there are also similar "AC mode" and "battery and AC mode" depictions)