Sorry to hear you are having this problem with a tree that is usually pretty trouble-free in our state. Agree you should not be seeing this after that much time unless the tree is struggling for some reason.

Is the root flare visible above ground? If not, is likely planted too deep; occasionally they even come this way from the nursery.... voice of experience after losing a 1 gallon pond cypress after several years that had been potted too deep by the grower.

Another possibility is root circling/girdling in the planting hole, which that drought could have exacerbated. More likely if you significantly modified/improved the fill soil or didn't cut, rough up, or uncircle roots before planting.

Squirrels leave a lot of tip damage on our CP where they don't completely chew off the shoot. Is not as apparent now that our tree is mature, but did stand out a bit when the tree was smaller. Doesn't sound like your problem, but is another possibility.

They can be great trees. Hope you can get yours sorted out.

Edit: Twine or wire left around the trunks of B&B trees can also cause problems.

I considered it possibly being planted too deeply or girdling roots last year when it went crispy after all the rain. The root flare is visible, so that wasn't it. Then I loosened a lot of the soil around the trunk to see if any of the roots looked like they were circling, but nothing. I did not improve the soil at all when it was planted, only added a layer of compost as mulch. I'm guessing it's time to call in the experts. It really is a shame as it looked great last week.

It is also considered an invasive by some sites, but mine has never gone anywhere. I attributed it to the deer.

Or possibly just a male tree? Believe most sold now are because of the invasive concerns... and the female's berries can make a mess of walks, streets, and other surfaces. Always good to confirm when buying one.