A job emitted this text as part of a warning:

The symbol 'TextInfo.ListSeparator' is banned in this project: Defaults to NumberGroupSeparator on .NET Core except on Windows.

However, the data table provided by warnings-ng-plugin in Jenkins does not display a space between "on" and ".NET":

The symbol 'TextInfo.ListSeparator' is banned in this project: Defaults to NumberGroupSeparator on.NET Core except on Windows.

After poking around with the script console, I believe the space character is lost in io.jenkins.plugins.analysis.core.model.DetailsTableModel.TableRow.formatDetails. It calls j2html.TagCreator.join, which is documented to remove spaces before periods and commas.