If characters or changes are made in the 80th column, the drawing is corrupted when saved.
1. On Mac OS X, load up PabloDraw
2. Edit a new drawing, put in e.g. 1234567890 ten times across the first row, copy that row to fill a page or so. You can even uniquely color each row to see how the error manifests afterwards.
3. Save test file, close file, reopen file.
result: the loaded file is not in the same state before the file was closed, as would be expected.