Hello Bindinir,
Thank you for sharing this picture. I was able to reproduce this issue without the DC block, (which isn’t required). It looks like a bug with our software at this very specific setup. If you change your stop frequency to 90MHz or 110MHz I noticed it no longer occurs and sweeps normally. I will explore this more. In the meantime are you able to change the stop frequency to one of these other values and continue use? If you encounter other issues you can let me know here or email me directly at aj at signalhound dot com. I can try to fix these before the next release.
Regards,
Andrew