I understand that. I did that countless times and i have also 2 NICs in the machines as i mostly use them as gateways. Suddenly, during reconfigure, the eth1 becomes eth0 and i have to switch cables because i am too lazy to run reconfigure again and it takes forever on PI 200. Also, reinstalling on the same machine, sometimes changes the order, (I marked the NICs IPCop style, using colors).
Since you have 2 NICs it may well be the case. It is something i tell you from experience, I know it should not happen, but it does.