If you are experiencing Lag or a Delay in the filtering, for example: the TVGuardian is muting after the curse word is heard, the problem is most likely with the cable or satellite box that you happen to have.
TVGuardian simply reads the closed-captions as they are streamed from the cable/satellite box to external devices, TVGuardian in this case. Around 85% of the cable/satellite boxes in homes deliver the closed-captions without errors and on time, and consequently work very well with TVGuardian. The other 15% deliver closed captions to external devices with poor quality and timing errors.
This is actually a violation of FCC rules and we've met with the FCC about it, too. However, without public pressure, it's not seen as a priority. That said, most of the Cable and Satellite receivers do work very well with TVGuardian.
You might try resetting your cable or satellite box and seeing if this helps. This will often re-sync the closed-captioning. You can also see if your cable or satellite provider will swap your box for another model. This usually takes care of the issues.