FreeBSD 12.0-stable /11.2 drops packets in bridge mode (dummynet)

[Aknet ISP]

Hello, dear All
I have some bridges (FB 8.4 on-board) which work perfect, but have problem with disk replacing in mirror (a srv has to be  stopped for replacing of disk).
We installed new FB 12.0-stable and met a problem - all packets drops in dummynet subsystem.
It looks that a packet goes into a pipe and doesn't return back from there
Income int - ix1
Outgoing - ix0
For test I send icmp from 10.10.10.1 (ix1 side) to 10.10.10.10 (ix0 side), tcpdump shows incoming packets at ix1:
listening on ix1, link-type EN10MB (Ethernet), capture size 262144 bytes
19:28:06.339329 IP 10.10.10.1 > 10.10.10.10: ICMP echo request, id 30347, seq 2675, length 64
19:28:07.402915 IP 10.10.10.1 > 10.10.10.10: ICMP echo request, id 30347, seq 2676, length 64
19:28:08.466494 IP 10.10.10.1 > 10.10.10.10: ICMP echo request, id 30347, seq 2677, length 64
ipfw pipe 100 config bw 15Mbit/s queue 465

00100  1637  137508 pipe 100 ip from any to 10.10.10.0/24 out via ix0

00110     0       0 allow ip from any to 10.10.10.0/24 out via ix0
ifconfig_ix0="up  -tso4 -tso6 -lro -vlanhwtso"
ifconfig_ix1="up  -tso4 -tso6 -lro -vlanhwtso"

cloned_interfaces="bridge0"
ifconfig_bridge0="addm ix0 addm ix1 up"
net.inet.ip.fw.enable: 1
net.inet.ip.fw.one_pass: 0
net.link.ether.ipfw: 0
net.link.bridge.ipfw: 1
net.link.bridge.allow_llz_overlap: 0
net.link.bridge.inherit_mac: 0
net.link.bridge.log_stp: 0
net.link.bridge.pfil_local_phys: 0
net.link.bridge.pfil_member: 1
net.link.bridge.ipfw_arp: 0
net.link.bridge.pfil_bridge: 0

net.link.bridge.pfil_onlyip: 0
I am ready to publish any additional info to investigate the problem.
With regards
Azamat B. Umurzakov
AkNet ISP