You say your sag was 35 mm before the crash and that you
incresed the preload to some unknown value immediatly prior
to the crash? I got that right?
Your sag with you and your gear should be 40 mm front 30 mm rear.
with an outside of 35 mm front and 25 mm rear. If in your case, if I have it correctly,
you decreased your sag even further from say 35 to 25 mm in the front.
I would hazard to say yes, the preload did contribute to your crash.
To have your bike just come out from under you while you are basically straight
up and down is really strange to say the least.
You can adjust the compression rate more or less by changing the wieght of oil and the amount
of oil which reduces the air volume inside the fork tubes. This air inside acts like a spring, an air spring.
The more air the softer the spring, the less the stiffer.
I would seek out a professional and have your bike looked at and setup
before you crash again.
Sounds to me like the thing is all whacked out.
Glad you did not get hurt!!