To pick up again on an old, persistent, issue.
In my (global) network of about 10 devices, some of the Windows 10 workstations do not communicate. They show connected/good on the my.zerotier.com dashboard, and all looks good in the tray “show networks” popup, but the nodes cannot be pinged, cannot ping others. This is ongoing, and as I said, on multiple, random PCs.
I did start this conversation before but did not follow through, apologies: