Poison Bomb's duration is wrong

Describe the problem. Be as specific as possible!:
The effect on the monster should scale from 4 seconds all the way to 10 seconds at max. The duration does not scale at all and remains 4 seconds for the entire time.
See table at Cygnus Skill Module in the extraction section for reference.

 Images of problem

Every DoT has bugged duration time in GMS.

The formula for the duration time (dotTime) is 4+d(level/5)
So at level 12 it should be:

4 + d(12 / 5)
4 + d(2.4)
4 + 2
6

No idea where they're getting their number from.

Just an update, my Poison Bomb is at level 18 now. It's still 4 seconds. Everything else seems to work fine. I've even tested its duration by timing it. It should be 7 seconds at level 18. The visual effect itself looks like it lasts around 5 seconds, but it only ticks four times (one per second).