DetectAdds repeating earlier parts of the recording


I have checked the app updates and there no available updates for my apps on the HDR-Fox T2.

I have the detectadds working all the time on channels that have adverts. I find that when I fast forward on a recording cleaned by DetectAdds The time line shows me moving froward with the fast forward. When I stop FF and play, I often find myself watching earlier parts of the recording. I have to FF again until I get to the part that I wanted to move to. Does anyone recognise what is going wrong?
Are you chase playing a recording whilst it is still recording using the -crop file?

This behaviour is normal but annoying. The Humax takes a snapshot of the hmt and nts files when it starts playing the file and doesn't know about later potions of the recording so if you start watching an hour long programme half an hour into the recording you can FF and skip during the first thirty minutes but not in the second thirty minutes.

BTW This thread will probably be moved to the CF forum
I am not chase playing. It could be days latter when I watch the recording. Never at the time of the recording or the removal of the adverts. As that is not the cause what can i do to stop it, because it can be really annoying to skip forward to find I am a long way back.
I haven't seen this except with chase playing.
I do sometimes see FF becoming jumpy after a cropped out ad break.
I haven't heard of other users experiencing this either.

Are you recording HD or SD or does it happen with both?
Does it occur following ad breaks
Is it repeatable ie if you start again and FF again does problem occur at the same point?
Is playback without FF OK?
Any other clues as to when problem does/ does not occur?
Could you send me the nts file for a recording that shows the problem with a note as to to when in the recording you saw problem.