It's not surprising, as your file uses <symbol> elements with viewbox= attribute. We do not officially support them yet. As you see they render OK, but obviously they have bugs because they were not tested up to now. In your file they likely originate from Illustrator.

Yes, symbols come from Illustrator. Is there any way to correct this by hand as I'd like to deeply test my file with gnome aisleriot before releasing the file ?

Could you please submit this to bug tracker so we would not forget about it?

OK

David