fibre glass

My parents had their flat-roof fiber-glassed over the summer. Fiberglass was applied over existing roof. Contractors drilled into the existing roof to fit the battens. The window was also replaced. When it rained the roof started leaking - small leak at first (above the window). The leak is...

Guys I decided to embark on a DIY bay window GRP roof....never again. Anyway it looked fine and more importantly it's been waterproof ever since. Fast forward 6 months, I have just noticed bubbling on one side? I have no idea why and hope you guys can help. Will it be fine? No water leaking...