Yeah, you've got a problem. First of all, this is what a good before and after sensor set should look like:
When the main three way cat goes bad, the sensor behind the cat starts following the voltage curve of the one ahead of the cat, because the cat is no longer converting the gases:
In your case, it does not look like the cat (yet), but more like the signal is interrupted or inconsistent, which would be more likely a wiring or electrical issue.