Child metadata does not overwrite parent metadata
The correct behaviour is described by vue-meta here:
https://github.com/declandewet/vue-meta#how-metainfo-is-resolved

I have created an example of the issue here:
https://github.com/jazoom/ream-minimal

Steps:
1. Right click and select "View page source" -> metadata displays correctly
2. Navigate to `Page 1` (which is a child of `Home`)
3. Right click and select "View page source" -> metadata is duplicated, despite the use of `vmid`

This causes issues with things like Facebook's parsing of OG tags.

I don't know how much of this is a bug with Ream's handling of vue-meta or within vue-meta itself.