Sony Vegas - Time freeze doesn't work

[Reiden]

Yesterday I had to edit a source, which was full with frame errors/tv artefacts.
Everytime the scene completly changed there was a pretty ugly frame error, so I had to remove them manually.
I removed them by splitting the video off the rest of the track and freezing the frame before the errors (changing the speed to zero).
In vegas EVERTHING looked perfect now and all of these frames were removed/freezed.

After 3hours of removing this shit everthing looked fine, but after I encoded it with vegas the frame error appeared again.
Some of the frames are removed how they should be but some didn't disappard althought I used the same method on every single one of them.

Before encode:


In Vegas (after freezing the frames)


After encode



I don't know what the hell happened, because the frame from the version after the encode didn't even exist in the version before the encode...

Like I already said in vegas everthing looks fine, so I don't understand why the error appears again after the encode =/.