A few weeks ago the subtitles on recordings made on TV1 HD lost sync by 3 sec, the firmware is MTV3700TD 5.10, the TV is a Samsung 55in connected by HDMI and programs watched live of the TV are in perfect sync, it's only when played back on the Magic TV 3700 that the problem occurs and seems to be only HD recordings like TV1, the subtitles on Prime are OK but they are standard definition not HD so don't know if this is the issue.