What is the real crouchbug?
When you crouching and rolling to left or right, you can break the rolling animation to instantly get up. This is crouchbug. (should also call it quickstand bug)
You can break the rolling animation at any phase, at the start, in the middle, or at the end, doesn't matter when exactly you break it, it causes your charachter's hitbox to crash and your charachter will rapidly stand up.
Normally if the rolling animation finishes, you have a .25s delay at the end of this animation before you can stand up. Crouchbug (quickstand bug) lets you to also cancel this cooldown.
Why it gives advantage to the players?
Since the animations are being cancelled and the charachter's hitbox getting crashed, you will be unable to give headshot kill to the player who abuses this bug, meanwhile he can kill you easily with headshot.
The main problem with animation such as crouching, and rolling, thats why you'll notice if someone just crouching without rolling, his collision will crash too for some moment.
Crouhbug is a glitch which could be enabled on every server. The players voted it to be disabled, so achieving it by other ways is punishable.
We currently give 10 days of jail and mute to the player who does it.
GTA:SA is a 20 year old game and its engine is very poorly optimised to PC port. Also the physics of the game is depends on FPS. This means that somehow you will be able to do crouchbug by pressing certain keys, or perform a certain combined task.
By doing this you exactly know that you will get jailed.
What about synchronization?
There are crouchbug variations where in your POV (point of view) you don't see yourself doing the bug, but your oppent does see it.
To be able to do this way of crouchbug you still have to perform certain tasks & certain keypresses what a normal player would never do.
So doing this, will also get you into jail and mute.