Bulding pastes incomplete

As the title and then when using /undo to remove the partial building I get a message telling me I have to paste something to undo it. This is on a building I've been pasting in since 2017-ish. I've created a paste here:-

https://pastebin.com/Vzyy5uyt

Do you have any ideas on what might be causing this? Thanks.

Aha! Thank you. 🙂

Nice thank you.

I can confirm that Nivex's fix works