usfm2osis.py - fails to convert consecutive \qc markers

One verse in the USFM file contained three consecutive centered poetry markers:

\v 5 Iban in tuktuk niya siyusulatan sin manga kabtangan gulalan kaniya, amu in malawm in maana niya. Ini in gulalan kaniya,
\qc Dāira Babilun Bantug.
\qc Puunan sin Manga Babai Mangī'.
\qc Tuburan sin Kaharaman iban Kalumuan.
\m

Only the first \qc marker was converted. The other two were not processed.

OSIS:

<verse osisID="Rev.17.5" sID="Rev.17.5"/>Iban in tuktuk niya siyusulatan sin manga kabtangan gulalan kaniya, amu in malawm in maana niya. Ini in gulalan kaniya,
<lg><l type="x-center">Dāira Babilun Bantug.
\qc Puunan sin Manga Babai Mangī'.
\qc Tuburan sin Kaharaman iban Kalumuan.</l></lg>
<p type="x-noindent"><verse eID="Rev.17.5"/>