merging of GenBank contigs into a single sequence shows incorrect contig positions and coordinates are not shifted correctly

If a GenBank file containing multiple sequences/contigs is opened, the "Sequence reading options" dialog is shown. The second option allows to "Merge sequences into a single sequence to show in sequence viewer". One can also add a specific number of unknown symbols ('N') between the parts.

Unfortunately, the viewer overlays the contigs depending on their range. Also, the feature coordinates of the second and following contigs are not shifted by the number of N's introduced between the contigs.

The coordinates of the "source" features are correct, except that they are not shifted by the introduced N's.

Try to import the attached file for reproducing the issue.