I observed something that might be useful to add to this thread:
Been using Synergy v1.8.2 (May 2018) for a while with a simple Win10 -to- Win10 config. The clipboard issue has been a regular annoyance. Usually, just calling the synergy.exe UI on the server, and clicking 'Apply' to force a reset, is sufficient to solve the problem.
Today, even that trick didn't work, so I looked more closely, and observed the '(missequenced)' error. Using the 'Apply' trick on both machines failed to resolve the problem.
Looked a little deeper at the Windows Task Manager process table on the *se