In the generated djvu file, there is an offset of 1 between OCR text and scan.
See e.g page 27 of https://ia801202.us.archive.org/34/items/dollshousetwooth00ibse/dollshousetwooth00ibse.pdf
I am not 100% sure it is a bug in IAupload tool, as two files uploaded after this were OK.
Maybe there is some special char in some files that trigger the problem?
As a matter of fact:
djvutoxml A_Doll\'s_House_and_two_other_Plays_by_Henrik_Ibsen.djvu is OK
djvused A_Doll\'s_House_and_two_other_Plays_by_Henrik_Ibsen.djvu -e 'output-txt' gives SegFault.