The rigid velcro part is separating from the shoe strap. The strap is beginning to stretch and is not strong enough, getting weaker.  These shoes are not as nice and sturdy as they use to be.  Are you getting them from a legit seller?  They are not the same quality that Propet use to make.  I have gotten these shoes for my husband for many years.  I hate to say it but I know the velcro strap is going to give on him.  They were not worth the money.