I had to click "view solution" cause I could not understand the instructions. Can't still understand it.

fixed

Testing code doesnt modify data located at the 'packet' pointer.
But still you output should have correct length, like in the specification.
Most likely "cutting down" is result of two cases either too long output or incorrect overlaying pointers.

No terminating zero character is needed.
Count bytes and correct pointers.

The "Issue" category is assigned for issues regarding Kata implementation(e.g. solution testing code, description).
If you have issues with solving you should post in regular discourse category.