Exporting a graph generates a blank node as a predicate

[YoucTagh]

Issue Description:

After loading a graph in Corese (obo_2019-08-06.n3), saving it as a ttl file generates a blank node as a predicate. This results in an error when importing this saved graph.

Steps to Reproduce:

1. Load the graph obo_2019-08-06.n3
2. Save graph in Turtle as saved_graph.ttl
3. Load the saved graph saved_graph.ttl

Expected Behavior:

Loading the saved_graph.ttl without errors.

An error was generated :

Loading ttl File from path : /home/ytaghzou/Bureau/youctagh/nice/kgbot/IDSM/merged/obo.ttl
fr.inria.corese.sparql.exceptions.QuerySyntaxException Encountered ";" at line 13365, column 57.
Was expecting one of:
    <Q_IRIref> ...
   ...

Screenshots/Attachments:

Change .txt to .n3 to reproduce obo_2019-08-06.txt