Alright I managed to find the old arc_conv.exe which I already used and it's the exact same file so it has to be a change in detection indeed.
Running it in a sandbox and doing some basic diagnostics shows no indication of if doing anything sus either, so I'll trust you when you say it's a false positive.
Just be aware that in the current state Windows Security will block the source code from being downloaded unless Real-Time Security is turned off.
Thanks for the quick responses.