The way SP works is that your computer works as both the server and client, so it suffers from the same problems in the code.
Please ignore Noisemaker's post. He's talking about a completely separate issue. Nextdelay on arrows prevents any one target from taking Strafe damage faster than every 4th frame, which is not a bug and works as intended.
The Strafe bug prevents strafers from reaching /2 breakpoints with enough IAS. The game will show you firing at 2 fpa, but the client will only recognize you firing at 3 fpa, causing "phantom" shots and possibly desynching you.