I have a large number of PCAPs which I use for automated testing. For security reasons, the Source and Destination IP addresses are changed (with a seed) before sending with tcpreplay. The seed is the same every time so that the output addresses are the same each time.
This was working fine up until recently. Now, when the PCAP is fuzzed with tcprewrite, the Source and Destination MAC addresses also sometimes change (but not always):
Input: "SourceMACAddress":"66:77:88:99:aa:bb","DestinationMACAddress":"00:11:22:33:44:55"
Output: "SourceMACAddress":"01:00:5e:99:aa:bb","DestinationMACAddress":"01:00:5e:33:44:55"

It means hundreds of tests fail because the Output no longer matches the Expected Output.

I'd attach an example PCAP, but I can't see where I can do that.

Oracle Linux Server 9.1
tcpreplay version 4.4.3