Out of curiosity I searched "water in taillights" in the 2014+ forums and didn't run across any post on the subject. Only water in trunk.
I did find this using an internet search:
2014 Kia Forte Tail Light Technical Service Bulletins (aboutautomobile.com)
I did find this using an internet search:
2014 Kia Forte Tail Light Technical Service Bulletins (aboutautomobile.com)