I haven't been playing tntwars so I'm saying this based off the results pages, but the results pages suggest the bug isn't fixed.
When you tested would've been this game:
https://cubedcraft.com/games/tntwars/results/10547/ which shows the game ending with 14 kills and 14 deaths.
Another example of the game ending with less than 15 deaths on a team
https://cubedcraft.com/games/tntwars/results/10783
There's a trick/exploit to getting more than 15 kills a game, but usually it's impossible because of the bug which is why I can see tons of players getting 14 kills but very rarely 15 kills.