You would have to inspect it without cutting the filter open, like
@Glenda W. did on the Endurance by cutting inspection windows in the assembled filter. On the Toyota filter, the base end of the center tube goes against the flexible rubber ADBV, so when the filter guts are all held tight by the leaf spring, then the leaf spring should be seated down on the end cap "resin ring".
Yeah, even if the leaf spring is seated well, we all know by now that there may not be a perfect seal for various reasons as seen many times now. The only filter with a leaf spring that seemed to be designed right was the OG Ultra with the fiber seal on the end cap, and the leaf spring was stamped smooth and also fit tight on the ID of the fiber gasket to add another layer of sealing.
Could be one factor on why the Toyota filters are so inefficient is that they are internal leakers.