[Koha] Zebra rebuild error

[rocky bang]

hi everyone,

I have koha 3.8 install on server.
I tried to reindex the zebra server using following commands.
export KOHA_CONF=/path to .xml file
export PERL5LIB=/path to kohaclone

perl misc/migration_tools/rebuild_zebra.pl -b -r -v

and it starts reindexing but i got following errors:

Zebra configuration information

================================

Zebra biblio directory = /etc/conf/koha-dev-domv/var/lib/zebradb/biblios

Zebra authorities directory =
/etc/conf/koha-dev-domv/var/lib/zebradb/authorities

Koha directory = /opt/kohaclone

BIBLIONUMBER in : 999$c

BIBLIOITEMNUMBER in : 999$d

================================

skipping authorities

====================

exporting biblio

====================

21901....................................................................................................


Records exported: 21928

====================

REINDEXING zebra

====================

11:19:48-30/08 zebraidx(8646) [warn] Unknown register type: 0

11:19:48-30/08 zebraidx(8646) [warn] Unknown register type: n

11:19:48-30/08 zebraidx(8646) [warn] Unknown register type: y

11:19:48-30/08 zebraidx(8646) [warn] Unknown register type: d

11:21:00-30/08 zebraidx(8646) [warn] Unknown register type: u

11:21:29-30/08 zebraidx(8646) [warn] MARC: Bad offsets in data. Skipping
rest

11:21:29-30/08 zebraidx(8646) [warn] Record didn't contain match fields in
(bib1,Local-number)

====================

CLEANING

====================

Please help me on urgent basis as I am facing   problem on production.

thanks in advance.