NAT download discontinue

[wzs993636]

Sorry, I am working hard on my English.
My env:

Platform: XenServer
Versions: OPNsense 19.7.1-amd64
NAT: yes
High Availability: yes

I download large file often discontinue. So I want that iperf3 to test my network and I found the same problem.I guess it is a problem with High Availability. Because the pfsync interface traffic gets high of the problem.This problem is easy to reproduce. The attachment is my iperf3 test result. Thanks.

[  4] 4417.00-4418.00 sec  76.1 MBytes   638 Mbits/sec
[  4] 4418.00-4419.00 sec  69.7 MBytes   584 Mbits/sec
[  4] 4419.00-4420.00 sec  73.5 MBytes   614 Mbits/sec
[  4] 4420.00-4421.00 sec  68.4 MBytes   576 Mbits/sec
[  4] 4421.00-4422.00 sec  74.6 MBytes   626 Mbits/sec
[  4] 4422.00-4423.00 sec  69.3 MBytes   581 Mbits/sec
[  4] 4423.00-4424.00 sec  68.6 MBytes   575 Mbits/sec
[  4] 4424.00-4425.00 sec  75.6 MBytes   634 Mbits/sec
[  4] 4425.00-4426.00 sec  69.5 MBytes   583 Mbits/sec
[  4] 4426.00-4427.00 sec  73.3 MBytes   615 Mbits/sec
[  4] 4427.00-4428.00 sec  67.8 MBytes   568 Mbits/sec
[  4] 4428.00-4429.00 sec  75.6 MBytes   635 Mbits/sec
[  4] 4429.00-4430.00 sec  71.5 MBytes   600 Mbits/sec
[  4] 4430.00-4431.00 sec  19.3 MBytes   162 Mbits/sec
[  4] 4431.00-4432.00 sec  0.00 Bytes  0.00 bits/sec
[  4] 4432.00-4433.00 sec  0.00 Bytes  0.00 bits/sec
[  4] 4433.00-4434.00 sec  0.00 Bytes  0.00 bits/sec
[  4] 4434.00-4435.00 sec  0.00 Bytes  0.00 bits/sec
[  4] 4435.00-4436.00 sec  0.00 Bytes  0.00 bits/sec
[  4] 4436.00-4437.00 sec  0.00 Bytes  0.00 bits/sec
[  4] 4437.00-4438.00 sec  0.00 Bytes  0.00 bits/sec
[  4] 4438.00-4439.00 sec  0.00 Bytes  0.00 bits/sec