I wouldn't necessary call this an issue so much as the way it is designed to work. The Velcro tabs are actually a new feature on the cloudkilts, and has already been mentioned, the cloudkilt is now more conical shaped. The first versions were simply a rectangular shaped piece of cuben fiber with hemmed edges. The top edge had a velcro closure on each end and a piece of shock cord inside the top hem to tighten/cinch the waist up. There was also a loop on the 2 top corners. Now it seems that they have listened to some of the users and made the improvements.
I do wish that the cloudkilt was a bit wider, say as much as 10 - 12 inches, at least towards the bottom. This would allow the bottom edges to stay closed during longer/wider strides, but depending on the stride, may not stay closed for each and every one of them. Also, I would not suggest adding anything that secures the bottom edges together. For those unexpected wide strides, the cloudkilt needs to be able to pull apart/open so the user can do so without resistance, and to lessen strain on the material.
If the one you have is too much trouble, I would suggest to get in touch with Matt and ask them if they can custom make one a bit wider... I have often thought of doing this, but havent't felt like going through the hassle of selling one to buy another... maybe one day I will... :)