Go on some random servers then aim at something precise, for exemple go to Phrantic lower YA, and aim at RA entrance.
1 - crouch (not important but you will move slower so you can see the bug easy) and fire a rocket without moving your mouse.
2 - Then start to crouch-walk forward and fire again without moving your mouse so you can compare.
3 - You'll see that your next rocket goes lower then first.
If not, that means that server admin put pm_ vars "0" in his server.cfg and it's ok.
The problem is not every admin know that he HAVE TO DO THIS and 90% of servers have this annoying bug.