How is water getting inside this waterproof roofing?

Is the roof vented? Or the eaves?

EDIT: It is very likely condensation, particularly if the house is concrete or stucco. Houses have to breathe. Vents should have been put in under the eaves instead of sealing up the space with solid materials.

Call the manufacturer for any tips. Sounds like you got it.
Good luck

There really are no eaves. it is comprised of single sheets of corrugated plastic overlapping each other. We we put it on it was a solid plane that sloped upwards for run-off. But the family did lower the back end, but it’s still waterproof. I’m wondering if this movement disrupted the ventilation.

Where the sheets overlap one another, is there any kind of sealant/adhesive used? I have a standing seam tin roof, on a sloped roof-line, and water does get in the seams. I have to have the thing resealed every couple of years, when the roof starts leaking again. (One of these days I’ll replace the whole shebang.)

It’s good work you’re doing… I applaud your efforts.

It is almost certainly condensation. That’s why attics are ventilated.

Maybe you can check again where the sheets overlap. Perhaps there is somewhere that wasn’t properly installed. The house should be well ventilated too to avoid condensation and molds build-up.