I had a brand new Envoy set up just the other day, and it leaked.
From the drain cap.
We put the drain cap on without the little gasket thingy behind it. I usually leave the drain caps in the owner's packet and put some on from a stash we keep on hand. I think the tubs look better with the black caps in place so I have a couple dozen in a bag. I just grabbed one and tossed it to my delivery guys - the gasket musta fallen out when they dropped it from my perfect throw.
Scared me! I haven't had a leaker in a long long long time - and I had a couple coming in to wet test later that day. Popped a new cap and gasket on and it was fine.
I found the gasket later - half under the spa. I think I'll go ahead and just leave it there for now... not a lot of choice.
8-)