You will not have the issue with the "Motion JPEG and PCM" codecs.
You can also use the 'H264' codec with the "Prefer CFR" option.
For more information, please refer to https://www.bandicam.com/support/tips/sony-vegas/
If you still have the problem, please send the video file to firstname.lastname@example.org
We will try to reproduce the problem you reported.