Rockstar used securom for the original disc release
Razor (an infamous piracy group) cracked the game shortly after release but only for Windows XP (Vista didn't exist yet)
Rockstar released the game on Steam "without securom" but in reality is just using Razor's crack
Fans eventually (like a decade later) realize there's Razor signatures in the executable on Steam
Rockstar pushes an update with a new executable, however this wasn't properly tested and is broken due to how the anti-piracy acts.