Frame bug in a video transition

Hello, I have a problem with my editing, indeed when I place a video transition, the transition displays for a few milliseconds an image that has nothing to do with the transition.

Pictures are better than words:

before :

and this is after the transition

But here is my bug, during the transition there's this red image that appears and disappears, this image is the game menu that Ive recorded but this part of the editing is at the very beginning of the editing so I don't see what it's doing here.
and if I remove the transition and look at the two videos there is not that red moment.

during the transition after this red iamge that dissapear 

Thanks ans sorry for my bad english