PC Day of the Zed Beta: Cannot achieve Seasonal achievement Eternal Punishment

[Servothehusky]

I cannot achieve the last seasonal achievement "Eternal Punishment", Complete wave 15 on endless hard or higher difficulty on Netherhood.

I have attempted this twice on a official hardwire server and Play solo offline and did not achieved it both time even those it told me I did after wave 15. I have tried both time to die at wave 16, and leaving wave 16.

 

[Servothehusky]

Actually, I solved this issue, Joining another game in progress and completing that wave regardless on what wave it is on will achieve the "Eternal Punishment" Seasonal achievement.