Photoset Post appearing as a Photo Post?

[Alistair]

Hi guys,

We've had a custom theme which has been working correctly for a long time. Posts with multiple photos were rendering as Photoset Posts but we're now finding that new posts of this kind are rendering as if they were single photo posts. Here's a stripped down example of what's in our custom theme:

{block:Posts}

  {block:Photo}...{/block:Photo}

  {block:Photoset}...{/block:Photoset}

{/block:Posts}

It doesn't appear to be affecting older multiple photo posts, only new posts.

Has anyone else come across this issue?

Thanks

Alistair H.