Unable to load projects in solution, when path contains a variable

In my .net solution, there are some paths containing a variable name like this:
` `

CycloneDx complains with these errors as it cannot locate these projects:
> Project file ".......\AB.Config.Model.csproj" does not exist

These variables are defined in a separate file: Directory.Build.targets

Is there a way to either:
1) Let CycloneDx know where these variables are defined ?
OR
2) manually specify these variable values ?

No source file or test is named. Start by reproducing the failure with a ProjectReference containing $(ConfigSrcDir), then inspect project loading and how Directory.Build.targets properties are evaluated. Done means projects using defined path variables load successfully, with a regression test or documented manual-value behavior.

Written by the indexing model from the issue text.