SW4's loopback 0 will be redistributed from eigrp to ospf on R4, this route will show up as a 'OSPF" route learned via R4 on SW2 because of the AD (110 vs 170), ospf route is preferred over eigrp external route, so SG is not complete.
workaround# 1 - advertise SW4's loopback 0 via eigrp network command on SW4;
workaround# 2 - filter the redistributed SW4's loopback 0 ospf route when it comes in to SW2 or change the AD on SW2 to prefer eigrp external route over ospf for SW4's loopback 0