net/sockstats: quiet some log spam in release builds

Updates #13731

Change-Id: Ibee85426827ebb9e43a1c42a9c07c847daa50117
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

net/sockstats/sockstats_tsgo.go

@@ -18,6 +18,7 @@ import (
 	"tailscale.com/net/netmon"
 	"tailscale.com/types/logger"
 	"tailscale.com/util/clientmetric"
+	"tailscale.com/version"
 )
 
 const IsAvailable = true
@@ -156,8 +157,12 @@ func withSockStats(ctx context.Context, label Label, logf logger.Logf) context.C
 		}
 	}
 	willOverwrite := func(trace *net.SockTrace) {
+		if version.IsUnstableBuild() {
+			// Only spam about this in dev builds.
+			// See https://github.com/tailscale/tailscale/issues/13731 for known problems.
 			logf("sockstats: trace %q was overwritten by another", label)
 		}
+	}
 
 	return net.WithSockTrace(ctx, &net.SockTrace{
 		DidCreateTCPConn: didCreateTCPConn,