Puppet's tongue disappears in Record view

I've just got it working, but I don't know why. I tried hiding the tongue layer and putting a rectangle in its place - in the layer above the hidden tongue. This made the rectangle act as a mask in Ch, so I could see the tongue just where the rectangle was - not outside it.

I deleted the rectangle and put a copy of the tongue randomly on his cheek. In Ch, I couldn't see the new tongue, but the original tongue showed up correctly in his mouth.

I have now pasted in place a copy of the tongue in the layer above the original tongue - and this works. If I hide the upper layer tongue, the original tongue is still visible in Ch. If I hide the original tongue and just show the new tongue, nothing shows in Ch.

So I now have two tongues - one hidden and one showing - and this looks as it should in Ch.

Weird.

Thanks for your offer to look at the puppet, but it seems to be working well enough now.