PowerDNS AXFR - ;; communications error to x.x.x.x#53: end of file

Using PowerDNS, we got into an issue with transferring a single domain object (/24) from our primary to our secondary DNS server.

This /24 is part of a larger RIPE block, /22, and is not automatically transferred. The remaining /24 domain objects transfer just fine.

As you can see from below emitted output, the axfr transfer from ns0 to ns1 stops halfway.

beelze@ns1 ~]$ dig @ns0.x.x.x.x -t axfr x.x.x.in-addr.arpa

; <<>> DiG 9.9.4-RedHat-9.9.4-61.el7 <<>> @ns0.comsave.nl -t axfr 
x.x.x.in-addr.arpa
; (1 server found)
;; global options: +cmd
x.x.x.in-addr.arpa. 604800 IN   SOA ns0.x.x.x.nl. 
servicedesk.company.nl. 2019012815 10800 1800 1209600 10800
0.x.x.x.in-addr.arpa. 604800 IN PTR no-reverse-yet.company.nl.
1.x.x.x.in-addr.arpa. 604800 IN PTR no-reverse-yet.company.nl.
10.x.x.x.in-addr.arpa. 604800 IN    PTR no-reverse-yet.company.nl.
[...]
188.x.x.x.in-addr.arpa. 604800 IN   PTR no-reverse-yet.company.nl.
;; communications error to x.x.x.x#53: end of file

A tcpdump on ns0 doesn't show much that helps troubleshooting?

13:56:45.927143 00:0c:29:16:2f:8e > 00:00:5e:00:01:03, ethertype IPv4 (0x0800), 
length 1954: (tos 0x0, ttl 64, id 28824, offset 0, flags [DF], proto TCP (6), 
length 1940) 185.52.208.19.53 > 185.52.208.27.59863: Flags [P.], cksum 0x1a1f 
(incorrect -> 0xf316), seq 2936827176:2936829064, ack 487100677, win 227, options 
 [nop,nop,TS val 582294609 ecr 974940634], length 188828565*- q: AXFR? 
x.x.x.in-addr.arpa. 100/0/1 0.x.x.x.in-addr.arpa. [1w] PTR no-reverse-yet.company.nl., 
1.x.x.x.in-addr.arpa. [1w] PTR no-reverse-yet.company.nl., 
10.x.x.x.in-addr.arpa. [1w] PTR no-reverse-yet.company.nl., 
[...]
188.x.x.x.in-addr.arpa. [1w] PTR no-reverse-yet.company.nl. ar: . OPT UDPsize=1680 (1886)