Bind9 - can't transfer zone

Hello,

I've encountered a strange problem with zone transfer. I'm an admin of Bind9 DNS server that is acting as a slave for few domains. One of the domains is not transfering (other from the same master transfers fine).

Bind9 error in the log is:
'xfer-in: error: transfer of 'domain.com/IN' from XXX.XXX.XXX.XXX#53: failed while receiving responses: FORMERR'

When I try "dig AXFR @XXX.XXX.XXX.XXX domain.com" the error is:
Code:;; Got bad packet: bad bitmap
1195 bytesand a hex dump.

Tried tshark while running the "dig AXFR", seems fine until:
Code:<Root>: type NXT, class Unknown, next domain name <Root>
Name: <Root>
Type: NXT (Next Domain) (30)
Class: Unknown (0x77c2)
Time to live: 134219008 (1553 days, 11 hours, 3 minutes, 28 seconds)
Data length: 256
Next Domain Name: <Root>
RR type in bit map: MB (MailBox domain name)
RR type in bit map: NULL RR
RR type in bit map: PTR (domain name PoinTeR)
RR type in bit map: HINFO (host information)
RR type in bit map: NXT (Next Domain)
RR type in bit map: NIMLOC (Nimrod Locator)
RR type in bit map: SRV (Server Selection)
RR type in bit map: A6 (OBSOLETE - use AAAA)
RR type in bit map: SSHFP (SSH Key Fingerprint)
RR type in bit map: Unknown (53)
RR type in bit map: Unknown (54)
RR type in bit map: RKEY
RR type in bit map: TALINK (Trust Anchor LINK)
RR type in bit map: OPENPGPKEY (OpenPGP Key)
RR type in bit map: Unknown (63)
RR type in bit map: HTTPS (HTTPS Specific Service Endpoints)
RR type in bit map: Unknown (66)
RR type in bit map: Unknown (68)
RR type in bit map: Unknown (70)
...
...
RR type in bit map: Unknown (2034)
RR type in bit map: Unknown (2035)
RR type in bit map: Unknown (2037)
[Malformed Packet: DNS]
[Expert Info (Error/Malformed): Malformed Packet (Exception occurred)]
[Malformed Packet (Exception occurred)]
[Severity level: Error]
[Group: Malformed]Output of "dig @XXX.XXX.XXX.XXX domain.com any" is OK, it's just the transfer that is failing.

I even tried:
Code:perl -MNet::DNS -wE 'my $r = Net::DNS::Resolver->new(); $r->nameservers("XXX.XXX.XXX.XXX"); for my $rr ($r->axfr("domain.com")) { $rr->print }'that we found at https://lists.isc.org/pipermail/bind...ay/104613.html
No output, but tshark show exactly the same traffic as "dig AXFR".

I got my hands on the .zone file from master, named-checkzone said "OK".

Our Bind9 is version 9.16.15 on a Gentoo server.
The master server is also Bind9.

I'm out of ideas. Anyone encountered this problem? Any solution, please?
Let me know if you need more info.

Thank you

Tets