Metadata Overview Error "We can't load your filters"

Problem

I entered a filter in the Metadata Overview macro, but when I save the macro, the search doesn't work correctly.

When I go back to edit the macro, I get an error message. It reads

We can't load your filters
We had trouble with <CQL term>. Try refreshing the page, but you may need to re-enter your macro parameters.

An error is thrown in the log.

2018-08-13 14:22:59,441 ERROR [http-nio-8090-exec-1005] 
[confluence.metadata.macro.DefaultMetadataMacroService] 
getCqlV2SearchQuery Unable to perform CQL Search -- referer: 
https://example.company.com/pages/editpage.action?pageId=16910256 | url: 
/rest/tinymce/1/macro/preview | traceId: c836f8febe3261ac | userName: 
admincom.atlassian.confluence.api.service.exceptions.BadRequestException:
 Could not parse cql ...

Solution

You are affected by a known bug in Metadata for Confluence. Metadata field values or Confluence spaces which start with a number cannot be found via CQL search. This is due to a bug in Confluence.

We are tracking the bug over here: METADATA-690 - Getting issue details... STATUS