He had laryngitis a couple days earlier he said and to fill in the gaps if his voice went so that maybe why
I didn't realise this was the first time they had shown the full David Bowie set, story on the background to the original here: https://amp.theguardian.com/music/2018/oct/25/david-bowie-lost-glastonbury-headline-set-bbc
What an interesting story and I thought it was a bbc cock up! But knowing that they had limited time, why didn't they ensure Glastonbury had some bright act to switch to?Got to be bad planning!
I highly doubt that when Glastonbury do the artist lists they're thinking about what the BBC can film if a certain artist wants not to be filmed.