Is the TSR buffer cleared when channel ends?


I had live paused CBeebies for my son the other day, and then when he was ready, set it playing again. A while later he shouted that the TV had stopped. It had got to 7pm (real time) and CBeebies had stopped / shutdown. The buffer should have still had 20-30 mins left to play but it had jumped to live TV (i.e. no broadcast).

So I am conjecturing that when the channel stopped transmitting the TSR buffer got killed - which is pretty annoying.
As you say, this is annoying, if you press record rather than pause then the buffer is saved as a recorded programme, but if you pause it, the TSR buffer is only available as long as the live channel is still 'on-air'. What is even more annoying is that the buffered TSR is actually on the hard disk, but not available
From the box's point of view the channel will have changed (to BBC3/4). So presumably it deals with it the same way as if you change channel - starts buffering the new channel and dumps the old.
It doesn't dump the old TSR when the channel is changed, it carries on recording the new channel and sets a pointer to the start of the new channel TSR recording, however the previous stuff is still on the hard disk until it is overwritten, it is possible to recover the previous TSR using Niceplice, Notes HERE see Note 7 'make a permanent copy of the previous program in the Time Shift Buffer'