I was going to post this in the main forum, but thought it may be better here in case I was wrong and didn't want to confuse newer kiters.
I flew my first foil kite yesterday, chrono 15m with ozone bar. I had to undue the CL on the fly while my buddy was flying it and attached it to my setup and noticed a problem in my opinion.
Without getting into crazy particulars I built my own line set to have a massive throw and 16 inch depower(it's too much but wanted it at the time). Regardless, I had to make my own flag out line coming from the swivel thru the CL b/c the length was so much larger. I allowed for 4 inches of slack thru the CL. 2 months went by and my flag out line was smack dab against my CL fully powered. So I made a new one...2 months later same thing. At this moment I believed in shrinkage, b/c my center lines did not lengthen.
Anyway, I'm waving this guys brand new ozone bar and kite around in the air and the leash swivel is snug up against the CL. So I just had a look at one of Gunnar's vids and saw when he boosted you can see the same thing. IMHO this causes the center line attached to the flag out line to shorten. Not a major issue, but one could see it as a major issue, b/c then that line is suffering massive amounts of load instead of the the depower dyneema rope 3.5mm taking all of it which normally does and it is rated at 3000 pounds vs a smaller line taking 600 pounds.
Here's one pic from a jump fully powered after I fixed my flag out line you can see there is slack: