Chain noise in reverse

So I've noticed a bit of noise coming that sounds like the chains are slapping some metal when I back up. It is usually only like a "clunk" and then doesn't seem to happen any more. Everything seems to be working properly in both forward and reverse. The chains are new (15 hours on them). The idler chains are properly tensioned. The chain tensioners are in good shape. When I oil them, there appears to be a few shiny spots on the tops of the third set, but no sign of wear anywhere.

It's on an 8x8 avenger... Any thoughts?

worn sprocket.... chain jumps on teeth making a clunk noise as it falls off the top of the teeth

Great.. What is the best way to check the sprockets for wear? If I'm gonna do one, I'd like to check the rest to see if any of the rest need work...

Check to see if the tips of the teeth are sharp. If the sprockets are good, what might be happening is the shiny top chain is getting tensioned at the top or bottom in reverse, and getting rubbed against something. And in forward, the other side of the chain is getting tensioned, and the top is not rubbing. Check the surroundings of that chain to see if there's something that could contact with the chain.

I did some looking today after a bit of use this past weekend and I noticed the chain tensioners were all the way down, and there was a fair amount of slack on the bottoms. I moved them up and they seemed sticky. I grabbed some brake kleen, a screwdriver and some shop towel and cleaned up the channel they ride in. Then sprayed them (the ends of the tensioner) with a silicone spray and manually moved them up a little - way better. On a ride down the street, the noise was all but gone and the last bit seemed to come from the left side first tensioner "clicking" as I drove. It was just the plastic piece clicking.. I'm going to check the sprockets this winter, after hunting season, and make sure they are in good shape and pull the chains and tensioners and clean everything up..