I'm having an issue with thumbnails on these two channels.

I can usually manually create one, but i would say about 90% of the time it will not create any further thumbnails.

I don't get any errors, and this doesn't occur with recordings made on other channels.

Any thoughts, or has anyone else experienced this?

I sometimes find the first two or three thumbnail images of a particular programme are all identical. Sometimes, but not always, pressing blue to reset thumbnails sorts this.

Have you tried this?

i don't think that you can do that whilst you are in the middle of watching something though.

I don't have the auto thumbnails on.
I usually start the recording, then put in a thumbnail when the programme i want to watch actually starts (i have 5mins auto-padding on!). Then i watch the programme, maybe after 20 mins i don't want to (or can't!) watch any more, so whilst watching i then create a thumbnail to bookmark my position.
It looks like it has done it, but then when i exit out, only the first thumbnail exists.

It is absolutely fine for recordings on other channels, but these two it seems one thumbnail is all i get!