Investigation: Why are some old Comment is Free liveblogs rendering incorrectly in DCAR?

[From CP](https://groups.google.com/a/guardian.co.uk/g/dotcom.platform/c/9dHMpgfqRK4):

> Was looking at this old community project from 2017 https://www.theguardian.com/commentisfree/live/2017/mar/03/what-even-is-a-hipster-join-our-live-look-at-the-week-to-discuss-this-and-more
>
> and it should look more like this
>
> https://www.theguardian.com/commentisfree/live/2017/mar/03/what-even-is-a-hipster-join-our-live-look-at-the-week-to-discuss-this-and-more?dcr=false
>
> Another from the same series, [here](https://www.theguardian.com/commentisfree/live/2016/aug/05/milennial-sex-and-trump-meltdown-join-our-readers-space-for-a-live-look-at-the-week) should look more like [this](https://www.theguardian.com/commentisfree/live/2016/aug/05/milennial-sex-and-trump-meltdown-join-our-readers-space-for-a-live-look-at-the-week?dcr=false)
>
> But some of them, eg [here](https://www.theguardian.com/commentisfree/live/2017/apr/28/has-brexit-poisoned-british-politics-join-our-live-look-at-the-week), are fine ...
>
> Do you know what's happened and if this might be a wider issue with older liveblogs?

Start by comparing the linked Comment is Free liveblog pages with and without the dcr=false parameter, then trace the differing rendering paths in DCR. Determine why some older liveblogs render incorrectly while others from the same series do not. Done means identifying the cause and documenting the affected scope or a specific fix path.

Written by the indexing model from the issue text.