Bicycle Mechanics - Bontrager wheel noise

I have a sealed bearing Bontrager rear wheel that began to click( more like a loud pop) when climbing in the larger cogs. I changed my wheelset out for another set to confirm it was indeed the wheel & not something like a crank or seat post. I also checked the quick release. I finally decided the bearings must need adjusting. After disassembly & inspection the bearings seem nice, smooth and solid.
One thing i did notice was that the cassette lock ring was not at all tight & the freehub is pitted from the cogs. The cassette is a custom setup of loose cogs & not pined together.
I have not taken the wheel out for a ride, but i wonder if the clicking/popping was due to loose cassette cogs.
Anyone else have this experience?

it very well be the cassette, try tighten it up and see if the popping has gone away .

If the cassette is Shimano 10-speed check to see that there is a 1 mm spacer behind the cassette. Without that the lockring will not tighten correctly. The recommended torque should be on the lockring, something like 35 or so nm (neuton meters). It's not essential to use a torque wrench, just be sure it is good and tight.

Thanks everyone! That has to be it.