when he's filmed or photographed doing factory visits, meeting members of the public etc, and they're all the same cast of actors
Well that's what I was thinking - and this is certainly true.
That is - if Putin only does super carefully stage managed appearances - why does he then need a double for security purposes?
Further - Putin doesn't strike me as someone who does anything he doesn't want to do. It's hard to imagine him thinking in categories like: "those poor factory workers have been waiting for me - I cannot disappoint them! Send the double instead."
If Putin wanted to, he could sit at home all year without coming out - and literally nobody would say a thing or think any worse or better of him.
He does what he wants, when he wants.
The facial differences seem to be related to Botox. If he got the shot just recently - then he's all puffy. If it was a while ago, his face starts returning to normal.
I think it's very strange that he gets Botox injections, but then politicians are usually vain people.