I have the same issue on both sides of my Flyer LE abdominal spar (can I call it a spar?). I've left the velcro bound in place as I believe it will keep the fissure from progressing and it will hold the spar together even if the crack some day reaches the other side. You may be able to get a replacement spar from Tiffen (I was able to replace the chest spar on a Pilot that developed an even more egregious fracture and sheared all the way through near the shouder). The conundrum is, if you replace the piece you may develop the the same problem again. I have a 32 inch waist and when I tightly cinch the vest it flexes the material beyond what it can handle without eventually developing fractures. My Flyer vest may not be cosmetically ideal, but there's no loss in function.
It's unfortunate that the Flyer and Pilot don't use the same material material as the EFP for the same purpose. I've had an EFP vest for 15 years and there's not a sign of a fracture as the material is much more resilient. Your best bet may be to reapply adhesive velcro in the exposed region and see if the fracture progresses to the point where it's a nuisance However, now that the velcro isn't in one piece you've lost your secondary means of keeping the spar in one piece and functional if there's an eventual break.