Well I've discovered some more plumbing issues, have the builder coming today hopefully to take a look. In addition to my concerns about that one return, I've discovered 3 leaks/drips at the filter. Both the input and output lines from the filter have a very slow but very consistent drip, as does the filter drain plug itself. I had noticed the pad was staying wet but for the past few weeks the entire filter body and most of the pipes were covered in condensation from the warm ambient temp and the cool pool water flowing through. Now that ambient temps have dropped some and the condensation is gone, I realized the pad is staying wet and discovered these drips on a closer look.
To make matters more difficult, there are no unions anywhere in the plumbing. The fittings are threaded into the filter and then pipes are glued from there outward. So there's no tightening these fittings as they sit or removing them to apply sealant/etc, without cutting pipe.