docfx metadata crashes with "The given key was not present in the dictionary"

**DocFX Version Used**:
2.28.3

**Template used**: (`default` or `statictoc` or contain custom template)
`default`

Run
`docfx metadata ./docfx.json`

Getting "The given key was not present in the dictionary":
```
docfx metadata ./docfx.json -l Verbose
[17-12-12 11:14:03.708]Info:[ExtractMetadata]Using msbuild Z:\Prog\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin as inner compiler.
[17-12-12 11:14:04.076]Info:[ExtractMetadata]Loading projects...
[17-12-12 11:14:15.720]Warning:[ExtractMetadata]Project 'D:\Work\R-n-D\XFW3\Src\Transfer.Common\Transfer.Common.csproj' does not contain any documents.
[17-12-12 11:14:15.733]Warning:[ExtractMetadata]Project 'D:\Work\R-n-D\XFW3\Src\ReportService\ReportService.csproj' does not contain any documents.
[17-12-12 11:14:15.736]Warning:[ExtractMetadata]Project 'D:\Work\R-n-D\XFW3\Src\Transfer\Transfer.csproj' does not contain any documents.
[17-12-12 11:14:18.156]Info:[ExtractMetadata]'D:/Work/R-n-D/XFW3/Src/Configuration/Configuration.csproj' keep up-to-date since '12.12.2017 11:01:12', cached intermediate result 'D:/Work/R-n-D/XFW3/Src/Configuration/obj/xdoc/cache/obj\3waufjop.pbh' is used.
[17-12-12 11:14:18.326]Info:[ExtractMetadata]'D:/Work/R-n-D/XFW3/Src/Utils/Utils.csproj' keep up-to-date since '12.12.2017 11:01:13', cached intermediate result 'D:/Work/R-n-D/XFW3/Src/Utils/obj/xdoc/cache/obj\wfcni3xu.zzc' is used.
[17-12-12 11:14:18.333]Info:[ExtractMetadata]'D:/Work/R-n-D/XFW3/Src/Interop/Interop.csproj' keep up-to-date since '12.12.2017 11:01:13', cached intermediate result 'D:/Work/R-n-D/XFW3/Src/Interop/obj/xdoc/cache/obj\vgtfa01t.uok' is used.
[17-12-12 11:14:18.968]Info:[ExtractMetadata]For git repo , can't find remote branch in this repo and fallback to use local branch [feature/callcontext]: fatal: no upstream configured for branch 'feature/callcontext'

[17-12-12 11:01:19.877]Warning:[ExtractMetadata]Invalid cref value "!:IXDatagramProcessor" found in triple-slash-comments for XDatagramProcessorOracle defined in ../Src/Storage.Oracle/Persistence/XDatagramProcessorOracle.cs Line 16, ignored.
[17-12-12 11:01:19.877]Error:Error extracting metadata for D:/Work/R-n-D/XFW3/Src/Configuration/Configuration.csproj,D:/Work/R-n-D/XFW3/Src/Core/Core.csproj,D:/Work/R-n-D/XFW3/Src/DataSources/DataSources.csproj,D:/Work/R-n-D/XFW3/Src/DataSources.Common/DataSources.Common.csproj,D:/Work/R-n-D/XFW3/Src/DevTools/Common/DevTools.Common.csproj,D:/Work/R-n-D/XFW3/Src/DevTools/ConfigSchemaEngineer/ConfigSchemaEngineer.csproj,D:/Work/R-n-D/XFW3/Src/DevTools/DataSourceInspector/DataSourceInspector.csproj,D:/Work/R-n-D/XFW3/Src/DevTools/DomainEngineer/DomainEngineer.csproj,D:/Work/R-n-D/XFW3/Src/DevTools/DotnetCliTool/DotnetCliTool.csproj,D:/Work/R-n-D/XFW3/Src/DevTools/JsDomainEngineer/JsDomainEngineer.csproj,D:/Work/R-n-D/XFW3/Src/DevTools/ModelEngineer/ModelEngineer.csproj,D:/Work/R-n-D/XFW3/Src/DevTools/SqlEngineer/SqlEngineer.csproj,D:/Work/R-n-D/XFW3/Src/DevTools/TypedDataSourcesEngineer/TypedDataSourcesEngineer.csproj,D:/Work/R-n-D/XFW3/Src/DomainObjects/DomainObjects.csproj,D:/Work/R-n-D/XFW3/Src/Interop/Interop.csproj,D:/Work/R-n-D/XFW3/Src/Libs/Microsoft.Unity/ObjectBuilder/ObjectBuilder.csproj,D:/Work/R-n-D/XFW3/Src/Libs/Microsoft.Unity/Unity/Unity.csproj,D:/Work/R-n-D/XFW3/Src/Libs/Microsoft.Unity/Unity.Configuration/Unity.Configuration.csproj,D:/Work/R-n-D/XFW3/Src/Libs/Xtensive/Xtensive.Sql/Xtensive.Sql.csproj,D:/Work/R-n-D/XFW3/Src/Libs/Xtensive/Xtensive.Sql.Oracle/Xtensive.Sql.Oracle.csproj,D:/Work/R-n-D/XFW3/Src/Libs/Xtensive/Xtensive.Sql.PostgreSql/Xtensive.Sql.PostgreSql.csproj,D:/Work/R-n-D/XFW3/Src/Libs/Xtensive/Xtensive.Sql.Sqlite/Xtensive.Sql.Sqlite.csproj,D:/Work/R-n-D/XFW3/Src/ReportService/ReportService.csproj,D:/Work/R-n-D/XFW3/Src/Server/Server.csproj,D:/Work/R-n-D/XFW3/Src/Storage/Storage.csproj,D:/Work/R-n-D/XFW3/Src/Storage.MsSql/Storage.MsSql.csproj,D:/Work/R-n-D/XFW3/Src/Storage.Oracle/Storage.Oracle.csproj,D:/Work/R-n-D/XFW3/Src/Storage.PostgreSql/Storage.PostgreSql.csproj,D:/Work/R-n-D/XFW3/Src/Storage.Sqlite/Storage.SQLite.csproj,D:/Work/R-n-D/XFW3/Src/Transfer/Transfer.csproj,D:/Work/R-n-D/XFW3/Src/Transfer.Common/Transfer.Common.csproj,D:/Work/R-n-D/XFW3/Src/Utils/Utils.csproj,D:/Work/R-n-D/XFW3/Src/XML Schemas/XML Schemas.csproj: The given key was not present in the dictionary.
```

The error "The given key was not present in the dictionary" happens with some combination of proejcts, I couldn't find a single project which makes it happens.