If you go back through this thread, you can find the following post that I made several months ago:
I am sorry to hear that you are having this problem. We would be happy to send you a set of lock washers that will correct the issue. We have only heard this complaint a very few times over the years, but understand that this is causing you (and the others that have posted here) frustration. We apologize for that frustration. For anyone experiencing this issue, please contact Panamorph at 719-266-2680 or firstname.lastname@example.org and we will be happy to send out a set of lock washers to correct it. We are also including a set of lock washers on all UH480 systems going forward and also note that the DC1 design was engineered when it was released a couple of years ago with a locking pan head screw system for precise alignment.