NSI Balance gel chipping

[Jade_mul]

Hiya, I’ve had a lady after a week have her gel overlays chipping, I use Nsi balance gel , does anyone have any ideas why this would be happening, is it something I’ve done ? I don’t have this issue at all with gel polish so I’m presuming it’s not down to my prep ?

 

[Jade_mul]

 

[Kylie.huds]

I think it is something at client's end.