Mystery bad pre returns

Currently my only problem with LJ is this problem - when it's not affecting me I can jump 250+ constantly and the only thing I have to do is complete adding a 6th and 7th strafe. When the problem isn't affecting me I can LJ quite high - I did the 253 block and 255.4 stats for the brief period this problem went away. But it always returns and when it does my jumps are useless, because my pre plummets to 260 or less no matter what I do.

demo: http://www.megaupload.com/?d=KY74QLK0

Basically what happens is when I get ready to do a lot of strafes or strafe quickly, my pre plummets to 250-260ish right when I take off. The speedometer shows 270+ the whole time, but right when I take off the pre strafe shower shows garbage pre and my jump is gimped - my jump is so short that it throws my strafes off. When I do just pre-strafe (1 strafe) I get 270+ every time.

When not experiencing the problem I can jump like this:

Distance: 255.462332 MaxSpeed: 336.853667 (60.888) PreStrafe: 275.965667 Strafes: 7 Sync: 85
1 11.408 0.000 15.5 100
2 11.888 0.899 17.4 91
3 10.052 0.000 15.3 90
4 8.478 0.000 14.3 90
5 6.368 0.000 13.5 80
6 7.777 0.000 17.8 53
7 4.917 0.000 5.8 90

because I can get the pre I need and stafe well also. Otherwise I can't jump for crap.

Hold A / D longer into the jump and W to the end of the pre = win