A non-critical assertion fails on saving project with related documents that are stored in files with symlinks in its path

Scenario:

1. Create a folder with a symlink in its path.
2. Copy "data/samples/CLUSTALW/COI.aln" to the folder.
3. Open the file.
4. Build a phylogeny tree for the alignment. It should be saved into the same folder.
   Expected state: there are two documents in the project, the objects have relation between each other.
5. Save the project.
   Current state: an assertion is triggered:

   ProjectParsing.cpp, line 106, method toRelativeRelations().
   

This assertion is not critical. A path that is stored in the objects relation is not in the canonical form.