Even though there is both surge protection and battery backup on Tablo, live TV gets jumpy and locks up to the point program gets behind in time. I have to reboot DVR to correct this.
Have you tried watching live TV with the harddrive disconnected? If your problem disappears, then it is probably a harddrive problem. Give it a try and see what happens.
When playing back a recording does it do the same thing?
…and do you have an HDMI tablo? or network’d one? Which device/app are you using to watch/access your tablo?
How is your tablo [and “viewing”] connected to your network?