I'm getting traces/shadows after using Track Matte Key, why?

[kazj63697131]

Hello,

As you can see here - https://imgur.com/a/LgQUQri - i'm getting shadow/reflection of the object that i'm using track matte key to expose, why is this and can I remove it?

I have tried using Luma instead of Alpha for the composite, and it reduces it, but does not eliminate it. I've also played around with the blend mode and Darken seems to reduce the shadow a bit, but it's still there. When I use Dissolve in blend Mode I get this speckled effect - https://imgur.com/a/Pm17VZ7

..not sure if that helps shed any light on the issue.

It has already been suggested that the opacity on the alpha that I have Track Matte Key on may not be 100%, but I have checked this and it is indeed 100%.

I'm out of ideas so if anyone can help i'd really appreciate it.

Adobe Premiere Pro CC 2018

Windows 10

[Meg The Dog]

Are you confident there is nothing on the matte source than the 100% white area and the 0% black?

It looks like there might be a shape with low luminance - on it - and that is the part that is transparent.

MtD

[kazj63697131]

Thanks so much, it did indeed have another layer there.The layer was a .mogrt imported from After Effects and it had an extra stroke applied to it which was invisible in After Effects but registered as a shadow when the TMK was applied in premiere.  It was so difficult work it out because it was completely invisible in AE. All i had to do was create a slider for that layer and import it along with the .mogrt, then make sure it was invisible (0%) in PP.  Thanks for insisting i double check the project as I finally sorted it out. 

[RobShultz · Accepted solution]

Also please double check to make sure that there are no drop shadows or semi transparent items associated with the layer.

[kazj63697131]

Both answers essentially pointed in the right direction, but RobSchulz specified a drop shadow, which was the closest to the stroke thickness that was causing the issue.

Thanks again both.