Parallel subtests share *ipn.Notify pointers (e.g. runningNotify). When multiple subtests reached the same phase concurrently, they all wrote to the shared notify's InitialStatus field without synchronization, triggering the race detector. Fix by shallow-copying *ipn.Notify before setting InitialStatus, so each test iteration works on its own copy. Updates #19380 Change-Id: I9dd40037e02146166f006f4f7c1ddcc47adba191 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>