Red rectangle appearing on exported video file

Hello community,

These days I returned to finishing an older project ,which I asked about here tiem ago, but many settings are different now, so I'm posting a new thread for  new problems (hope you don't mind).

Here's the situation:

1 - First problem I have is with a long, red rectangle that appears when I export the video. It seems to follow the cueball, as if it's tied with a null to a motion tracked place, but there isn't anything like that in the layers settings, so I don't know where this is coming from. In a few previous versions of the file this red rectangle line isn't appearing, but I don't see anything that could have a relation to this in terms of settings. Does someone have an idea what might be causing this?

2 - Another problem I have is with the frosting effect of the ball. The frost effect is done with a jpg frost texture and a solid using the alpha matte and a mask expansion, along with the roughen edges effect. You can see that besides the frosting, the effect is growing beyond it in black and again I don't know what's causing this. I tried to reduce the scale of the Ball frost pre comp,I tried to reduce the scale of the Frost Alpha solid you can see in the pre comp tab, I tried to reduce the mask expansion of it too, but nothing seems to help with this.

Here are a few screens and a video to help you get a view of the situation:

I'll be thankful for any suggestions!

Regards