Cast When Damage Taken + Curse on Hit

I'm using the following skill gem setup to automatically cast high level curses when hit:

Cast When Damage Taken (CWDT) Level 1 - Ice Nova Level 1 - Curse on Hit (CoH) Level 17 - Conductivity Level 18

This setup works fine but for some reason does not work if the curse gem is low level.

For example:

CWDT(1)-Ice Nova(1)-CoH(17)-Conductivity(1) Does not work
CWDT(1)-Ice Nova(1)-CoH(17)-Vulnerability(1) Does not work
CWDT(1)-Ice Nova(1)-CoH(17)-Elemental Weakness(1) Does not work

but as stated above

CWDT(1)-Ice Nova(1)-CoH(17)-Conductivity(18) Works

In the case of failed curse application, Ice Nova does go off on hit but the linked curse is not applied.

I'm reporting this as a potential bug as the behavior is strange and does not seem to be documented anywhere.

Please let me know if this is in fact a bug or if it's intended, but undocumented behavior, or if CWDT plus CoH are not intended to be used together.

Thanks in advance for your help.

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The /debug bug number is 2,142,376,787

I took a screenshot but it's really not relevant to this bug report. I'd rather not go through the hassle of uploading it unless absolutely necessary.

I can give details about my machine if absolutely necessary but this doesn't seem relevant either. I'm running on Windows 7 64-bit.

http://www.pathofexile.com/forum/view-thread/1049640#p8788899
http://pathofexile.gamepedia.com/Version_1.2.2

"

We have restricted skills to only work with a single trigger gem at a time. Skills supported by multiple triggers will be disabled and won't work with any of them.

Two trigger gems in the same links is supposed to invalidate them. The bug there seems to be that you got it to work under certain circumstances. I'm guessing it's because when you have a higher level spell, your CwDT can't trigger it, so the game doesn't try to apply two trigger gems at once. The Curse on Hit is somewhat redundant there anyway. The CwDT casts the curse without the need for the curse on hit. You're just limited by the levels.

I see what's happening here.

CWDT(1)-Ice Nova(1)-CoH(17)-Conductivity(1)

does not work because Conductivity is effectively supported by 2 trigger gems.

Once a curse is leveled so that CWDT is no longer able to support it, the setup begins working once more.

Bottom line - this appears to be working as intended.