Index: trunk/src_plugins/rbs_routing/install.c
===================================================================
--- trunk/src_plugins/rbs_routing/install.c	(revision 38859)
+++ trunk/src_plugins/rbs_routing/install.c	(revision 38860)
@@ -38,6 +38,9 @@
 	rnd_coord_t l1x = RBSR_G2R(line->x1), l1y = RBSR_G2R(line->y1);
 	rnd_coord_t l2x = RBSR_G2R(line->x2), l2y = RBSR_G2R(line->y2);
 
+	if (line->RBSR_WIREFRAME_COPIED_BACK)
+		return 0;
+	line->RBSR_WIREFRAME_COPIED_BACK = 1;
 
 	if (obj == NULL) { /* create new */
 		if ((line->x1 == line->x2) && (line->y1 == line->y2))
@@ -75,6 +78,10 @@
 	double sa, da;
 	rnd_coord_t cx, cy, r;
 
+	if (arc->RBSR_WIREFRAME_COPIED_BACK)
+		return 0;
+	arc->RBSR_WIREFRAME_COPIED_BACK = 1;
+
 	sa = 180.0 - (arc->sa * RND_RAD_TO_DEG);
 	da = - (arc->da * RND_RAD_TO_DEG);
 	cx = RBSR_G2R(arc->parent_pt->x);
@@ -124,6 +131,15 @@
 		}
 
 		pcb_arc_modify(pa, new_cx, new_cy, new_r, new_r, new_sa, new_da, NULL, NULL, 1);
+
+		/* A change in an arc typically means change in connected lines; the lines
+		   on our target tn are tuned but lines of innocent bystander twonets are
+		   not. Arcs of those bystander twonets are updated and are getting
+		   here because all arcs of an affected point-segment is checked */
+		if (arc->sline != NULL)
+			rbsr_install_line(ly, tn, arc->sline);
+		if (arc->eline != NULL)
+			rbsr_install_line(ly, tn, arc->eline);
 	}
 	return 0;
 }
Index: trunk/src_plugins/rbs_routing/map.h
===================================================================
--- trunk/src_plugins/rbs_routing/map.h	(revision 38859)
+++ trunk/src_plugins/rbs_routing/map.h	(revision 38860)
@@ -32,6 +32,7 @@
 #define RBSR_G2R(v)  ((rnd_coord_t)rnd_round((v)*1000.0))
 
 #define RBSR_WIREFRAME_FLAG user_flg1
+#define RBSR_WIREFRAME_COPIED_BACK user_flg2
 
 int rbsr_map_pcb(rbsr_map_t *dst, pcb_board_t *pcb, rnd_layer_id_t lid);
 void rbsr_map_uninit(rbsr_map_t *dst);