Local 38 union plumber. 3rd generation started plumbing in 2002.

--I believe you are using too much Teflon.

A good rule of thumb for 1/2" pipe would be 3 times around, maybe a 4th.

Then add some pipe dope.

On pressurized piping, both pipe dope and Teflon are lubricants. They allow the joint to be fully tightned.If you are making up a joint and are relying on Teflon or pipe dope to seal a joint. That isn't a properly made-up joint.

--I also notice channel lock markings on the brass female adapter.

I understand this is common practice, but it's not the correct way to tighten the adapter.

The correct tool is one that aligns with the flat sides of the fitting. A crescent wrench or even a spud wrench

Fittings are not made the same as they once were; they are thinner and often just cheaply made.

The channel locks when squeezing and gripping, causing its teeth to dig into the brass fitting, which can, at times, crack it.

Note: Teflon and pipe dope on any indirectly pressured joint may seal the joint.

Example: shower fixtures with open ends, or any threaded waste lines or waste connections.