I just tried it. I created a 16 bar segment in GB (at 120 bpm) using smart strings then emailed it to my self. Opened it up in Cubasis and then imported it into a new project that was set at 120 bpm. The result is an audio event with exactly 16 bars.
I’m not sure what problem you are having. Although, if you have a lot of reverb and echoe on the track then it will export at a longer length then 16 bars. This is referred to as the effects tail.
See my image below to see the results of pasting in a 16 bar track from GB.
