[Elecraft] Artifacts in headphones when monitoring my transmitted CW

[kevino z]

I just got my Heil Pro 7 iC hooked up to my KX3. I made sure the Mic Bias was on, and set my monitor level to 5. Whenever I transmit CW (even with 0 W out), there is a strange artifact that happens as the Dit and Da's finish, kind of like they have a very short burst of a chirp or similar sound as they are finishing the transition from on to off.
Sorry, it's quite hard to describe. As I change the WPM to about 25 or so, the effect appears to go away, I am assuming because the time between the transmitted CW is reduced. However, it is quite noticeable and annoying around 15-20 wpm, where I am hoping to be at.

I tried it with a simple pair of earbuds and the artifact is there too, so I do not believe it to be related to the choice of headphones. 

Does anyone have any ideas or suggestions on what it may be?
And more of importantly, how to minimize / get rid of it?

Thank you 
-Kevin (KK4YEL) 

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